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 momoculars 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. Designed to be used with the ATN line of Smart HD Optics: BinoX 4k, OTS LT, and OTS 4T. ATN Extended life Battery Pack w/USB Cable Cap & Neck Strap Holder ACMUBAT160N