Replacement BT-66Q Battery for Topcon / Sokkia BT-66Q for Field Controllers. Compatible with model numbers RC-3, FC-2000, FC-2500, FC-120, FC-100, FC-250, FC-200, GMS-2, GMS-2 Pro, GRS-1, GB-500, GB-1000, GPT-7500, GPT-9000. The 2600 mAh capacity rating...