VLTOR m4 gas block Front sight can be flipped up or kept down. When the front sight is folded down, there are 1913 piccatiny rails if you decide to run a different front sight. There are also QD sling mounts on both sides. There is some mild corrosion on middle two rail slots. Asking $30 shipped. Accepting PayPal only. Send payment as gift from friends and family unless you want to pay the 4% pp charge.