3500mAh Extended Battery + Cover For Sprint HTC EVO 3D Powerful grade A 3500 mAh true high capacity battery makes all the difference for the HTC EVO 3D user. Back Extended Battery door is included! This grade A cell battery features powerful Lithium Ion, so there is no memory effect either! Lightweight Lithium Ion battery is about 2/3 the weight of a comparable capacity NiMh battery! Notes: A new Lithium Ion battery's full performance is only achieved after the initial 2-3 complete charge and discharge cycles. Battery may not fit into desktop charging stands & some holsters & cases.