The Topcon BT-52QA is a 7.2V, 2700mAh NiMH on-board battery used with Topcon instruments such as the GTS-200, GTS-210, GPT-1003, GTS230W, GPT-3000, GTS-220, GPT-2000, and CTS-3000. It has three charging pins and fits the Topcon BC-27BR charger.
