Dont know much anout these and dont know how to test it. If you purchase and if something is wrong i will gladly accept the return.

This is a Humminbird Portable/Handheld System Fish/Depth Finder with a 4" x 5" display size. It is battery-powered and features a back light. It has a sonar sensor and comes with 2000 preloaded courses for fishing. The product is used and has not been tested.