These are texas instruments branded - one of the best in the usa.
1. Ti-34 (solar power only, no backup battery) with cover and chart - ghs 45.
2. Ti-36x (solar power only, no backup battery) - ghs 45.
3. Ti-30xa (battery: installed, has cover) - ghs 55
please review the pictures provided, take the time to do your personal research on the these devices ( if you must), then decide on which model you want to buy and call me. Thanks