The TRS-125 red dot sight builds on its predecessor with digital push-button control, user-selectable 12hr timer and over 15,000hrs of battery life. An IPX7 ingress rated monolithic main housing and durable low-profile mount with removable, skeletonized high-rise spacer put this sight at home on many small arms. Features: Push button w/10 brightness settings,15,000 hour battery life on cr2032,side load battery compartment,12 hour auto-off selectable, waterproof https://www.bushnell.com/on/demandware.static/-/Library-Sites-HuntShootAccessoriesSharedLibrary/default/dw02f3708b/productPdfFiles/TRS125_1LIM.pdf