TNT APS-X Air Cushion Barrel Kit for Gas Blowback Rifles 6.03 370MM.
Specially designed grooves in the barrel create an air cushion that guide the bb eliminating contact with the barrel's sides. The air cushion is also dispersed out of the barrel ahead of the BB.
As the BB is untouched by the usual air bubble on exit, there is a lot less deviation usually created by it.
This version is for GBB rifles and has 3 inner barrel/hop chamber positioning grooves to fit various brands.