Comp C2 from Aimpoint. 10,000 hour battery life, 2MOA dot. I've got about 4 cheap red-dots that I tried before I bought the Aimpoint. The dots suck, they don't hold zero, wash out in bright sunlight, battery life is poor, batteries are stored in bad positions, etc. Save your money, save the aggravation. Invest in the Aimpoint. I found it on sale for $389 from a dealer in Red Oak, TX.
jr