Kalashnikov K-21 M-LOK Rail For Sale https://gunsbuyerusa.com/product/kal...21-m-lok-rail/ Kalashnikov K-21 M-LOK Rail 90001488B UPC*811777021477 Four M-LOK slots on each side of the lower handguard Matching upper handguard with recessed 5 slot 1913 rail 2-15 slot M-LOK Proprietary rail sections. Four long screws & M-LOK nuts for lower rail Four short screws for upper handguard (BLACK) Lower length- ...