Forget the countless trips to the store to purchase batteries, the Pulsar PB8I Power Bank is a 5,100 mAh capacity USB rechargeable external battery pack that helps digital and thermal devices last up to 20 hours on a single charge during extended periods of usage. Ideal for the nighttime hunter who doesn&';t want to change batteries during stands or while in the field, the PB8I features a built-in charge level indicator and more than doubles the operational time of external equipment. Weapons mountable, this unit is waterproof and shockproof, allowing it to be mounted directly to a firearm or other device with a picatinny rail. Weighing just 7.8 oz., this power bank will increase battery life without greatly increasing the overall weight of the firearm. Included in Package Micro USB cable Features Rechargeable lithium-ion battery Built-in charge level indicator Designed to power digital devices / thermal imagers / night vision riflescopes Increases operational time of external equipment Weapons mountable Waterproof Compact and lightweight