The Hatsan Mod 55 air rifle caliber 4.5 mm. Monte-Carlo, the stock from Turkish walnut, plastic recoil pad, adjustable trigger pull. TRUGLO fiber optic micro-sights, adjustable horizontally and vertically. Manual and automatic safety, the choice is up to the shooter. The steel barrel is grooved mainly on the bearing (11 mm) for mounting a riflescope mount. The SAS system reduces recoil and rifle vibrations after shot. QUATTRO - a light regulatory trigger system.