It's not always we need a weather-proof PDA/PDAPhone, but occasionally the need arises out of nowhere. OtterBox is a company that develops different types of hard cases, to cater for such a need and to make your PDA/PDAPhone more suitable to use under extreme condition. I've received a OtterBox 1900 case and manage to get it out for a spin.
The OtterBox 1900 was built as a universal fit for the majority of PDA/PDAPhone. The hottest HTC celebrity TyTN II? No problem. The inner dimension of 1900 was able to accommodate any PDA/PDAPhone from Nokia 6120 Classic Smartphone to Dell Axim x51v (without extended battery). Flipping up the transparent hard cover in front, there is a membrane layer which is fully-sealed and replaceable. I was able to navigate on top of the membrane freely. It is soft, quite durable and no noticeable scratches after couple of days use.
The front was equipped with external slot to hold the stylus.
On the top, there is a quick access hole, for users to turn on the PDA/PDAPhone (if the power button is on top), or to bring out the headphone cable.
If there are too many things to access at the top like power button on the side (if you didn’t reassign the button to be accessible in front or playing some tricks), the user can assess to it by unlatching the top cover.

The bottom was backed by piece of rubber and when it closed, it is closed very tightly. Mostly the interests are to access to sync/charge port, or to use the mic when answering call. It’s funny when once I have an incoming call while I’m trying out the case, I can hear the voice from the other end by turning on the speaker phone but the receiving end cannot listen to my voice if I didn’t pull out the rubber.
Use the latch system at the back to insert/remove the PDA/PDAPhone.
The Velcro that found inside the case was to hold and position the PDA/PDAPhone, as well as outside for user to carry it.
And of course it’s much simpler to use with non touch screen Smartphone such as Nokia 6120 Classic - just use your finger to navigate the button on top of the membrane.

Conclusion
One must understand that OtterBox 1900 was intentionally built for PDA but not for PDAPhones/Smartphones. I’m just exploring its usability while I’m sure OtterBox has a lot more to offer on its new range of devices such as the BlackBerry Curve and Apple iPhone. In terms of application, the rugged OtterBox 1900 was designed to be water-proof, dust-proof , dirt-proof and drop protection (4-feet from the ground) without degrading its usability. It acts like a shield on top of your vulnerable PDA for it to continue to work under extreme condition. I can find its usefulness in mining industry, military, extreme sports & etc.