Sig Sauer Romeo M17 Enclosed Red Dot Circle Dot BlackSig Sauer Romeo M17 Enclosed Red Dot Circle Dot Black Fully enclosed, sealed, and purged optical system for ultimate protection; Designed exclusively for SIG SAUER M17 M18 pistols with SIG LOC mounting interface; Rugged 7075 aluminum housing with integrated gas deflector and anti reflection grooves; 2 MOA red dot 32 MOA circle reticle with independently selectable options; 15 brightness settings, including 3 optimized for Gen 3+ night vision devices;