The Trijicon RMR (Ruggedized Miniature Reflex) sight is the most rugged miniature red dot sight available. It is made from 7075-T6 aluminum to MIL-spec standards and has a patented shape that absorbs impacts and diverts stresses away from the lens, increasing durability. With eight available brightness settings, the reticle can be manually adjusted by pressing the plus or minus buttons on either side of the unit. To switch to auto adjust mode simply press both buttons simultaneously and release. To save battery life turn the optic off by pressing both buttons simultaneously and holding for 3 seconds. The RMR is a versatile sight that illuminates in any lighting condition.