 any conditions you know sand anything that can get into your optic that can really cause you problems and a closed optic is something that really puts you at that level where you don't have to you don't have to worry about anything so red dots are really tough most of them really tough really rugged and we we especially build ours the original premise of this optic came from the the romeo m17 which we developed for the us army to go on their m17 pistols m18 pistols