Recharge your batteries with this 18650 Batteries and Charger Set Perfect fits for W3 and W5 doorbell Comes with 2 x 18650 batteries - 3.7V 2000mAh As well as a 1 x 18650 USB charger  USB adapter not included 18650 batteries have a balance of capacity as well as power output, making them very versatile Compatible with a range of devices and kits Can be used with regulated and mechanical devices Power your devices with this 18650 Batteries and Charger Set for 22.99 pounds