Diamondhead Rear Combat Sight - Classic (Narrow "goal-post" Upper) - Folding Iron Sight Traditional round apertures with a narrow (goal-post style) upper housing Flips up quickly and smoothly for rapid deployment Folds down fast with the push of a button Proprietary deployment system ensures sight stays up securely & remains zeroed in combat situations Mil. Spec. Type III hard coat anodized 6061 T6 aircraft aluminum, finished in Black