BM3521S(re) BM3521S 3200mA / 7.2V (23Wh) Double O-ring specification. * Double O-ring compatible light modules LM5K2600S2, LM4.2K2200G2, LM5K1300S2, LM4.2K1100G2, LM5K-SP17-2 Included Parts: Battery module cap