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.