Package includes: 4 pack rollers. - 25 mm diameter rollers; shaft diameter 8 mm; load 5-40 kg (10-88 lbs) - 38 mm diameter rollers; load 15-65 kg (40-130 lbs) - 50 mm diameter rollers; shaft diameter 12 mm; load 25-80 kg (50-170 lbs) Stainless steel rollers Constructed of stainless steel for rust resistance and durability. They are waterproof, smooth, and quiet, delivering smooth, efficient operation with minimal vibrations. Spring press-in mounting Spring installation makes assembly easy. Push the spring in or pull it out from the opposite side to securely install the roller into the conveyor frame. Low noise The powerless roller runs without a powered drive, with very low friction and minimal sliding noise from transported items. This yields stable, reliable, and quiet operation. Please confirm roller size, frame width, and roller center spacing before ordering. Use scenarios - Retrofit gravity conveyors in manufacturing or packaging lines for smooth item transfer. - Build or upgrade DIY rolling carts, sliding shelves, or small conveyor systems in workshops. - Use in quiet, low-maintenance material handling in small factories or warehouses where powered drive is not needed.