Set of cylinders for PTW guns M16/M4 from Systema M130 spring. Compared to the previous version, which was made of aluminum, anodized finish (48g), this new cylinder made entirely of stainless steel SUS304 (84g). Change of material leads mainly to a greater strength, lubricity and abrasion resistance. Otherwise, all other internal stressed and performance parts are totally the same. Manufacturer made this change for the reason that if careless reload occurs from an airsoft pellet entering the space between the cylinder and the magazine, so in this place after load of the magazine can create small dent in softly side of older aluminum cylinder.