Without the use of an effective magnifier, owners of rifles equipped with a red-dot sight are only limiting their platform's effective range, since the 1X power of an RDS tube can't provide effective aiming at distance. The solution is to mount a total sighting system like the American Defense DUO 5 optics package on their carbine. The American Defense Spek Red Dot is powered by a single AAA battery, not those unique, hard-to-find batteries that power other red-dot optics. You can find AAAs at any hardware store, and the sight runs for up to five years on a single battery! Other features found in the American Defense Spek Red Dot include a 2 MOA dot complete with 12 diff Mfg: American Defense Manufacturing