1.Unpowered Stainless Steel Rollers In Set Of 8: This replacement steel roller is constructed of a stainless steel surface and galvanized end caps. The surface of the rollers is smooth, no burrs and capes, waterproof and durable. Oiled bearings have no jamming, rotate smoothly and ly, operate quietly, and produce minimal vibrations, ensuring smooth, efficient, and minimize friction 2.Fixed Roller Diameter And Roller Bar Diameter: Roller 25 mm (1') bar 8 mm (0.3'); Roller 38 mm (1.5') bar 12 mm (1/2'); Roller 50 mm (2') bar 12 mm (1/2'); Roller 60 mm (2.4') bar 12 mm (1/2'). Better adapted to most mobile projects, ensuring the stability and concentricity of the drum 3. Lengths Available: We have included specific roller sizes in the pictures, particular details include: Overall length of roller, Roller step length, Roller surface length, Roller diameter, Roller bar diameter, Wall thickness. There are standard lengths available to fit various projects, building layouts, and specific conveyor needs 4.Easy To InstallSpring Press In Installation: Easy swap out. With the roller's builtin spring, these replacement conveyor belt rollers ensure more convenient installation and disassembly, saving you unnecessary time and effort. Push the spring in or pull from the other side to fit the roller into the conveyor frame effortlessly