Toughest red dot you can buy... - Trijicon RM07 RMR Type 2 1x 6.5 MOA Adjustable LED Reflex Sight

I've had my RMR2 for 5 years now. It has NEVER let me down. I put about 10,000 rounds through my AR and I've only changed the batteries once. It is NOT meant to be a primary optic for a rifle. It's too small for that, it goes great with my Acog and I have another RMR2 I use on a side mount for my scoped AR10. FUNCTIONALITY & DURABILITY in a little package. It's expensive but if you want something that's going to last and work well for a long time, you can't go wrong with a Trijicon.