EDGI AEG (SRS) Dual Bore Barrel 420mm,  bronze.  One of the best inner barrel money can buy, i would say one of the essential upgrade for DMR or sniper rifle. RRP 140 from longbow

EdGi Dual Bore Barrel - 420

6.00mm to 6.05 ID
 

It's a used barrel,  not new, details below

Inner surface is spotless, the outter surface has some electric tape residuls (used to stablise the inner barrel in a slightly bigger outer barrel) and also discoloring due to being brass, but mainly cosmetics and do not affect the performance of the barrel. See pictures for more details