Motorola NNTN8128BR is a slim 1900 mAh Li-Ion IP67 submersible battery for APX portable radios. IMPRES battery charger required. 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.