Shop › B5 RAIL COVER M-LOK BLK B5 RAIL COVER M-LOK BLK $17.10 B5 Systems Rail Covers, 4 Pack, Fits M-LOK Rails, Matte, Black RCM-1256 Quantity: Add To Cart Added! B5 Systems Rail Covers, 4 Pack, Fits M-LOK Rails, Matte, Black RCM-1256