TACFUN Black Polymer Smart Flip up Folding Auto Deploy Front and Rear Tactical Sight Set Push Button Automatic Deploy Flip-Up Front and Rear Sight Towers Complete with A2 Square Post Assembly with Locking Retention and Precision Elevation Adjustments for Greater Accuracy. Mounting Decks Designed to be Used with Handgguardflattop Rails and Both Will Fit All 1913 7/8" Picatinny/Weaver Style Rails. Easy Quick And Secure Installation -Allen Screw Locking Clamp Rail Base Retention For Maintaning Zero Under Heavy Conditions. Solid Reinforced Polymer Construction. Lightweight & Built To Withstand All Conditions