Efest IMR 18500
Efest IMR 18500 V1 1100mAh 3.7V Rechargeable LiMn High Drain battery. Flat top.
Please note that due to their inherent safety IMR cells don't have a protection circuit built in. They should never be discharged below 2.5 volts or cycle life/performance will be reduced. Maximum charge voltage is 4.25 volts.