+3 BRT MarkBlue Gas Tube - BRT EXT GT-1-EXT $19.95 In stock Quantity: 1 Add to Bag Product Details The Black River Tactical MarkBlue Gas Tube is a premium quality gas tube used exclusively with the BRT EXT length gas system. The BRT EXT ( Extended ) gas system was created to provide OPTIMUM performance from 16" 5.56 barrels. The BRT EXT gas system is longer than the standard mid-length, but shorter than the Noveske Intermediate length. Note: Also fits KAC Legacy MOD0/1 and Wilson Combat 13.25" The distinctive "MarkBlue" dot allows easy identification of a genuine BRT gas tube and guaranteed performance. It is compatible with BRT MicroPin Gas Blocks, front site bases and low profile gas blocks. Includes a stainless steel gas tube and a stainless steel spiral coil spring pin. Save this product for later Favorite