The waterproof aspect was tested extensively and not a drop got in to ruin my route sheet. Better than other companies similar products. Main body is made of some tough as nails plastic. This will last me a long time.
Simpler than a map in a tank bag (while you're riding).
Nice little unit, no electronics, all manual. See at a glance your next turn and mileage. Of course you have to set up the sheet first, but a well made, simple unit. The knobs work with gloves on. Recommended.