ATN Extended Life Battery Kit - Don't let yourself be stuck without a functioning unit, because you didn't bring extra batteries to power your device. ATN Extended Life Battery kit and power pack can support your binoculars or monoculars for up to 15 hrs. You can use your devices longer and save money and the environment in the process. Enjoy your activities all day long - whether scouting, camping, bird watching, or surveillance. You can even power your none ATN devices, which are compatible with a micro USB. 10000 mAh Battery Pack USB to Micro USB with L Shape Connector Neck Strap with battery holder