The Plantronics Spare Battery for P620 is a replacement battery pack suitable for your calisto P620 and P620-M. It is a Li-ion polymer battery type which can be charge either with AC wall charger which will take 1.5 hours or a USB cable which will take 2.5 hours. It has the capacity of up to 7 hours talk time when fully charged.

Features:

* Li-ion Polymer battery

* To install remove battery door on bottom with tiny Phillips screwdriver

* Charges with AC wall charger (1.5 hours) or USB cable (2.5 hours)

* Provides up to 7 hours talk time

* 3.7V, 930 mAh, 3.4Wh

* Measures 2 ½” long, 3/8” tall by approximately ½” wide