OEM Motorola HNN4001A IMPRES,1800 mAh, NiMH battery.  

Compatible with HT-series, PR860 and MTX-series portables.

IMPRES batteries when used with an IMPRES charger provide automatic, adaptive reconditioning, end-of-life display, and other advanced features. Data is stored in the battery and communicated to the charger via a unique IMPRES communication protocol which is designed to maximize talk-time and optimize battery cycle life — all automatically.