Custom made silencer adapter for Hatsan air rifles with 1/2-28 tpi thread to attach your air gun silencer, and with M23x1 thread to fit the 26 mm O.D. shroud (including BullBoss).
Material is steel, blued. With thread protector. Through bore is 8 mm (0.315″) wide. Suitable for .177, .22. and .25 cal. Knurling pattern may be different than the one on the pictures.