BR-2/3AGCT4A is a 4 cell battery pack with Panasonic batteries BR-2/3AG cells. Together it gives 6V DC for the absolute feedback positioning of the FANUC ALPHA servo drives. On system notes, manuals and in other locations its listed as A06B-6114-K504; because it normally is fitted in A06B-6114, 6117, 7124, 6127 series amplifier modules.
These BR2/3AGCT4A are made in Japan. With a dimensional size of depth = 1.75in and height of 1.5in due to the 2/3 height of the Panasonic cell. Capacity is 2900mAh which should last with standard use on a single Fanuc servo amplifier of 2 years. Though Fanuc states that batteries whether on systems or drives should be checked yearly.