Great budget red dot from one of the best brands in the game - SIG SAUER ROMEO5 1x20mm 2 MOA Red Dot Sight

I'm not a sig groupie, but this is my second Romeo 5. I'm not a big fan of the CR battery just for the size but at the price here on OP can't be beat. I've had my first Sig 5 for six months no problems at all. It's held zero when switching from 5.56 to 9mm AR platforms through 500 rounds of both calibers.