This slider phone features a bright 2.4-inch screen, measures 4.1 by 1.9 by 0.7 inches, and weighs 4.8 ounces. As is the case with all vertical slider phones, you slide up the screen to expose a numeric keypad. I found the C905a easy to open and close with one hand; depending on where you place your thumb to slide it, however, you may end up with smudges all over the screen.

When you press the keys, they have a solid feel and a good amount of clickiness, and they each sport a raised bump, but since keys on each row run together without any dividers, determining where one key ends and another begins can be hard. Also, the top row of keys can be a little uncomfortable to press, since they are right up against the slide-up portion of the phone. Other buttons on the face, such as the call start/stop buttons, are small and might be tough to press if you have big fingers.

Build quality is good: The C905a feels solid in the hand, although I wonder how well the slider will hold up over constant use. Initially I found the battery cover difficult to remove; it didn't help much that the quick-start guide failed to mention anything about the battery compartment (call me crazy, but battery-installation instructions are exactly the sort of thing I'd expect in a quick-start guide).

The C905a's software is adequate, but after using a smartphone for the last several months, I can't help thinking that it feels antiquated by comparison--in navigation, and especially in aesthetics. The phone's various features are reasonably easy to locate in the menu system.

In my hands-on tests in the San Francisco Bay Area, I found the C905a's call quality just average. Voices weren't especially clear, but they had adequate volume.