Most literate people are familiar with at least some of the consequences of the print revolution of the 15th century, but far fewer are as aware of the much more profound change that occurred when rolls were replaced by codices–pages bound between covers–in the late Roman period.

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But several companies now sell wireless mice designed especially for laptop users for whom the laptop touch pad just won’t do. These mice are small, sleek, colorful gadgets that more fashion-conscious computer users can happily show off in an airport, in a coffee shop or on campus.

See a chart comparing the three mice

This week I tested three entry-level mobile mice designed for laptops, from Logitech (LOGI), Microsoft (MSFT) and Kensington Computer Products Group. These $30 mice include a USB receiver that plugs into a laptop, allowing the mouse to work wirelessly. When not in use, this receiver fits snugly beneath the mouse, turning its power off to save battery as it snaps into place. These mice are also somewhat smaller than regular mice so they can easily slip into a laptop bag.

Mobile mice are now more stylish than the traditional desktop mice, and like laptops and digital cameras, come in various shapes and colors. The mice I tested are available in pink, white, red, blue, orange and gray. Next week, the Microsoft mouse I used will be available in shades of pomegranate, aloe, dragon fruit (dark pink) and milk chocolate; a khaki-colored shade called crème brûlée will follow in June.

I tried Logitech’s $30 V220 Cordless Optical Mouse in black, Microsoft’s $30 Wireless Notebook Optical Mouse 3000 in aloe, and Kensington’s $35 Ci75m Wireless Notebook Mouse in orange. To gain some perspective on high-end mobile mice, I also looked at two pricier options from Logitech: the $50 V470 Cordless Laser Mouse with Bluetooth (instead of a USB receiver) and the $70 VX Nano Cordless Laser Mouse.

My vote for a favorite low-end mobile mouse had me struggling between portability and comfort. But overall, I found that the Logitech V220 offered the best combination of small size and usability. The Microsoft mouse was also comfortable to use, but its slightly bulkier size made it less portable, and it didn’t feel as sturdy as the Logitech. While the Kensington was the flattest and most portable, it wasn’t as comfortable to use as the Logitech or Microsoft mice.

To conserve battery, all three of these mice go into low-power mode after 10 minutes of nonuse, but none of them turns off completely. Battery indicators light up when juice is running low. According to company estimates, the Microsoft mouse has a battery life of over six months and the Logitech mouse has a battery life of up to six months. The Kensington mouse’s battery life was estimated to be three months. I didn’t use any of them long enough to prove the company claims.

These mice are compatible with Macs and PCs, and are plug-and-play — meaning you don’t need to install any additional software to make them work. I used each on laptops running Mac OS X and Windows Vista without any problems. The Microsoft and Logitech mice also can work with their own special software programs, but the extra features, such as reassigning a mouse button to open an application, aren’t really necessary for the average user.

The $30 Logitech V220 fit comfortably in my hand, with rubber grips on its sides and a generously sized, smooth-gliding rubber scroll wheel that made it easy to use. This scroll wheel can be nudged to the left or right for horizontal scrolling, a feature found on most of Logitech’s mice.

Unlike the Microsoft and Kensington mice, which show flashing red sensor lights, the Logitech uses an invisible optic sensor. This sounds cool, but because the mouse doesn’t use any lights, it can be left on accidentally. I did this a few times before remembering to stow the USB receiver in the mouse to automatically turn off its power.

Of the three, the Logitech mouse was the only one with a manual on/off switch — so you can turn it off without snapping the USB receiver into place in the mouse. This could save frequent travelers from having to detach the USB receiver every time they want to turn off the mouse, and could let people keep the receiver plugged into the laptop.

Kensington’s $35 Ci75m was the flattest mouse by far, making it a cinch to slip it into the outside pocket of my already full laptop bag on a train trip to New York. And this mouse has a bonus feature: It can work wirelessly or with a USB wire, which wraps up inside the mouse and serves as a backup in case the mouse runs out of battery. I tested this by removing the batteries and using only the USB wire, and it worked like a charm.

I also liked the way the Kensington USB receiver disappeared into the body of the mouse, while the Microsoft and Logitech receivers protruded a bit when stowed, adding to the thickness of the mouse when tucked into a laptop pocket.

But though this bright orange mouse received approving feedback from passersby, it wasn’t all that comfortable to use after a while. Its flatness saved room in my bag, but didn’t give my hand much support. It also felt flimsier than the Logitech, and its small wheel wasn’t as satisfying to use.

I received early test units of Microsoft’s $30 Wireless Notebook Optical Mouse 3000 in aloe, pomegranate and milk chocolate.

This mouse has rubber sides for a better grip, like the Logitech, and an arched shape for comfort. Its wheel is slightly smaller than Logitech’s, though its overall size was bigger and more like that of a regular mouse — not one designed specifically for mobile use. But even though the Microsoft mouse was larger, it didn’t feel as solid as Logitech’s; rather, it felt more like the thin Kensington. Its right and left buttons felt less stable, and its wheel didn’t roll as smoothly.

I did like Microsoft’s nod to new colors, and the aloe — a cool hue of green — was my favorite.

For people who don’t mind spending a little extra money on a mouse, the $50 V470 Cordless Laser uses Bluetooth, eliminating the need for a USB receiver altogether. It took only a couple seconds to pair this mouse to a MacBook with built-in Bluetooth, and it worked smoothly. A manual on/off switch on this mouse’s underside can help to conserve battery.

The $70 Logitech VX Nano Cordless Laser is sleek with shiny black accents and a silver-edged wheel. The “Nano” in this mouse’s name refers to its ultra tiny USB receiver, which sticks out only about a quarter of an inch when plugged in, so it can be left in a laptop at all times for ease-of-use. If needed, this receiver can be hidden away in the cavity of the mouse, under a snap-on lid. I used the VX Nano to glide around Web pages and Word documents with buttery smoothness.

No matter what mouse you choose to use with your laptop, most will be considerably more comfortable than touch pads and trackpoints, especially while working on long, mouse-intensive projects. But of the three lower-end mobile mice, the Logitech V220 Cordless Optical Mouse delivers the best combination of comfort and transportability.

The chart below (click on it to make it larger) compares features of the three mice described in this column.

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To make Bluetooth even easier to use in cars, most new luxury cars and some standard cars are sold with optional built-in Bluetooth speakerphone technology which doesn’t even require an earpiece. Some cars also come with built-in iPod integration, displaying song titles on the dashboard and controlling the iPod using buttons on the steering wheel, again to minimize distractions. One new built-in product, SYNC, the voice-activated system created by Ford Motor Co. and Microsoft Corp., lets users do both things hands-free: play music or make phone calls using simple voice commands.

The $120 Parrot PMK5800 uses voice recognition for a more hands-free experience.

This week, I tested two devices that bring Bluetooth technology to older cars in hopes of integrating hands-free phone calls and music with a car’s stereo system. I tried the $130 Venturi Mini from NextGen Venturi Ltd. (www.myventuri.com) and $120 Parrot PMK5800 from Parrot Inc. (www.parrot.com) on three cars made in 2000 and 2005.

Neither device offers a surefire solution; each is limited by your particular car and cellphone. But the Parrot sails ahead of the Venturi Mini by using voice activation for phone calls, something the Venturi Mini can’t do. Venturi’s version of “hands-free calling” requires initiating a call on the cellphone itself or by looking down at a tiny, grayscale screen and painstakingly scrolling through names of contacts. Furthermore, the Parrot worked after only a few steps, while the Venturi took much longer to set up and get going.

Both of these are one-piece black gadgets that plug into your car’s cigarette lighter and use FM transmitters to play on unused FM radio stations. Each has a tiny screen, though the Parrot screen is used solely to display the current station so as to match it with the radio. The idea is that after initially “pairing” a Bluetooth cellphone with one of these devices, the phone and device will automatically find each other whenever both are in the car and on, making calls easier and music a bit more hands-free.

The Parrot and Venturi Mini will only play music via Bluetooth using cellphones that have a technology called A2DP, which enables music streaming. More and more new cellphones have this technology, such as the Nokia 6555 that I used, but many — including Apple’s iPhone — don’t. Most people will play music by attaching an iPod or other portable music player to these devices using cables that come with them.

The $130 Venturi Mini doesn’t work with voice commands.

Neither the Venturi Mini nor the Parrot PMK5800 enable voice commands with music: songs streamed via Bluetooth are controlled using buttons on the devices, and music coming from a wired-attached player can only be operated using buttons on that player.

The Parrot isn’t as compact or as stylish as the Venturi Mini, but its best feature is unseen: built-in voice recognition software that guides you while using this device. If your cellphone has built-in voice-recognition software, which many do, you can plug in the Parrot and get started. Otherwise, contacts must be loaded on to the Parrot and assigned a voice tag. Large green and red buttons initiate or end phone calls, but speaking commands also works. A knob turns to different stations or can be pressed and turned for audible descriptions of menus. Three glowing Play/Pause, Skip Ahead and Skip Back buttons are easy to find without looking down so as to navigate through music.

While I was listening to music coming from one paired cellphone, my sister called me on another paired cellphone that I had forgotten I had in my purse. The music automatically paused, and the sound of a ringing phone came from the car speakers until I answered it by pressing the Parrot’s green button (speaking the word “phone” also works).

If voice tags are assigned to contacts in your phone, the name of the person calling can be announced over the speakers, like caller ID. Music automatically re-starts after a call ends.

I made calls on the Parrot by pressing its green button and speaking directions like “Call Allison Mobile” to call the correct number from my phone’s contact list. The voice recognition sounded a bit robotic, but almost always found the right number.

Most voice calls sounded rather clear to the people with whom I spoke, but in the car, calls suffered when stations were interrupted with static as I drove around the Washington, D.C., area. One major issue with relying on FM transmitters in major cities is the small number of unused radio stations. Static also affected streamed music, making it sound scratchy at times. Music playing from a cord-connected iPod had no trouble.

The same static problems arose with Bluetooth calls and music on the Venturi Mini. This device’s rectangular face has a scroll button in its center, which seems like it would be a useful addition. But this can’t be pressed down to select anything on the screen, which is maddening. Instead, selecting anything from the Venturi screen must be done using a separate button, as if it wasn’t even designed to be a hands-free device.

To set up the Mini, a paired phone’s contacts must be copied from the phone onto the device. Once these contacts are added, calls can be initiated through the device by finding the correct name on the screen using the scroll wheel and pressing more buttons to select that name and place the call. None of this involves voice recognition, and it’s all supposed to be done while you’re driving.

For all its faults, the Venturi does have a few features that the Parrot doesn’t, including the ability to display Bluetooth data — like the name or number of an incoming caller and a song title and artist — on your radio display if your car has this ability. But most older cars don’t allow this, and I couldn’t quickly figure out how it worked even while driving in a 2005 car. You can also charge devices through the Mini using a built-in USB port.

The position of a car’s cigarette lighter matters to the Venturi Mini and the Parrot. This plug is often positioned near the gear shift, and in my manual car, it would’ve been difficult to operate these gadgets while in fifth gear (I didn’t try). The location of this plug also determines how loud or soft your voice sound to callers. So as to not sound so far away during calls I tried to lean closer to the devices, but this isn’t safe while driving.

The Venturi Mini looks like a hip device, but without voice recognition software and a smart interface, it’s frustrating and dangerous to use. Parrot’s PMK5800 plugs in and works and its voice-recognition software makes it a true hands-free device that will improve the way you use Bluetooth in your car. Just look out for static, especially in big cities.

Edited by Walter S. Mossberg

Email mossbergsolution@wsj.com