Larger than a typical portable mouse the Orbit Mobile is nevertheless significantly smaller than Kensington’s full-size trackballs and small enough to fit comfortably in most laptop bags. And it isn’t much heavier than a travel mouse.
Kensington Orbit Wireless Mobile Trackball: Small but usable
The Orbit Mobile’s shape is a comfortable curve, with the 1.2-inch ball located on the downward slope, almost flush with the front edge. The crease where your palm meets your fingers rests on the top of Orbit's body, with your index and middle fingers resting gently on the ball. The ball’s optical-tracking movement is smooth and, depending on your settings, surprisingly precise—the Orbit Mobile's tracking isn't as good as that of the ExpertMouse, but it's much more responsive than Kensington's SlimBlade Trackball.
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The left and right sides of the Orbit Mobile are tapered, letting your thumb and pinky fall naturally on the left and right mouse buttons, respectively. The buttons are large and easy to press, even with your pinky (though not so easy that you end up pressing them accidentally), and the symmetrical design means the trackball is equally usable by righties and lefties. For cursor control and clicking, the Orbit Mobile is a very good device, and one that I, as a weight-obsessed traveler, found worth packing in my bag.
The Orbit Mobile’s scrolling feature, on the other hand, I sometimes found frustrating. Rather than a traditional mouse-style scroll wheel, or the mechanical scroll ring of the ExpertMouse, the Orbit Mobile features two touch-sensitive, arc-shaped pads—one curved around the left side of the ball, and the other on the right. When you want to scroll, you drag a finger up or down on one of these pads. (For me, it was easiest to drop my middle finger down off the ball to scroll.)
Out of habit, I frequently tried to use roughly the same amount of pressure that I’d use on my MacBook Air’s trackpad, but when I did so, the gestures occasionally weren’t recognized—or at least they weren’t recognized for the entire duration of the gesture. And scrolling itself was jumpy unless I slowed the scrolling speed using Kensington’s software (see below). That said, I also find scrolling to be jumpy on my ExpertMouse, so this may just be a “Kensington thing.” (What I wouldn’t give for an ExpertMouse with the smooth-as-butter scrolling of Logitech’s higher-end mice.)
Unlike Kensington’s other trackballs, the Orbit Mobile is a wireless device, connecting to your Mac using a tiny RF (radio-frequency) USB dongle that fits neatly inside the Orbit Mobile when not in use. I personally don’t have a problem with RF wireless—I find RF input devices to be a bit more reliable than Bluetooth versions, and for portable use, it’s nice to be able to keep Bluetooth disabled to conserve battery life—but if you’re anti-dongle, the Orbit Mobile won’t be for you.
Kensington Orbit Wireless Mobile Trackball: New, stable software
The Orbit Mobile works fine without any drivers, giving you standard cursor control, left and right mouse buttons, and simple scrolling. But if you install Kensington’s TrackballWorks software, you get a number of additional options. For starters, you get more control of cursor speed, and you can enable Inertial Scrolling, a useful feature (similar to Lion’s Scroll With Inertia setting in the Mouse & Trackpad screen of Universal Access settings) that gives scrolling some virtual momentum, letting you scroll through pages and pages of a document with a quick flick of your finger. You can also choose whether a downward gesture scrolls up or down.
(This feature works independently of OS X Lion’s own scroll-direction setting, letting you, say, use Lion’s new scrolling behaviour for your laptop’s trackpad but keep traditional scrolling for the Orbit Mobile.)
You can also choose the cursor speed and, separately, its acceleration curve; assign modifier keys for precision cursor movement (one for super-slow movement, another for restricting the cursor to a single axis); and enable the option to automatically move the cursor to the default button in any modal dialog.
Finally, you can configure what the Orbit Mobile’s two buttons actually do. While one button, either the left or the right, must be set to perform a standard mouse click, you can configure the other button, as well as a left/right “chord” (both buttons pressed simultaneously) to perform other actions.
The available options include a standard click, a right-click (Control-click), a double-click, a click-drag, Back or Forward (in your Web browser, for example), a modifier-key click (for example, Command-click), any keyboard shortcut, or one of scores of specific actions Kensington has provided. These options include shortcuts for pasting defined text snippets, navigating windows, controlling media playback, browsing websites, editing text, using Exposé and Mission Control, managing applications and windows, using Spotlight, modifying system settings, logging off or shutting down, taking screenshots, opening items, and much more. (I personally have the left button set to a standard click, the right button set to right-click, and the two-button chord set to close the current window [Command-W].) These customization options are great, but they'll make you wish the Orbit Mobile provided more than just two buttons.
Although TrackballWorks isn’t as flexible as Kensington’s older MouseWorks software—for example, you can’t choose different settings for each application, nor can you create multiple groups of settings.