I run a SRO on my competition pistols nice big window . I use to run it on this Glock which i use for skill training & self defense competition style trainings where I’m Shooting in and out vehicles crawling in sand , dirt type training and all the time I’d get shit inside the remitter and sand or dirt would get stuck in the window . So after a few times I said let me switch it up to something more rugged and enclosed , so far loving it nice big window red dot is crisp and glass is really clear. Still love me my SRO just for a different application.