A new release from RA-Tech designed to replace the hop-up inn GHK AK Gas Blowback Rifles. The RA-Tech CNC'd GHK AK Hop-Up can fit most of the GHK AK series with the exception of the early GHK AK GBBs with the DBoys lower receiver. Better check first your GHK AK GBB's version before you order this from your retailer.