Shop › B5 RAIL COVER M-LOK FDE B5 RAIL COVER M-LOK FDE $17.10 B5 Systems Rail Covers, 4 Pack, Fits M-LOK Rails, Matte, Flat Dark Earth RCM-1257 Quantity: Add To Cart Added! B5 Systems Rail Covers, 4 Pack, Fits M-LOK Rails, Matte, Flat Dark Earth RCM-1257