Material: The roller shutter wheel is made of high-quality, corrosion-resistant PU steel, which is sturdy and durable and has the characteristics of oil resistance, corrosion resistance, and rust resistance. Dimensions: The total installation height is 25.5 cm; the wheel diameter is 5 cm; the mounting plate size is 7.5 × 4.5 cm (length × width). Load capacity: The maximum load capacity of each wheel is 50 kg. Spring design: The telescopic shutter wheels can move vertically by 6 cm and automatically adjust the height to uneven terrain to prevent sagging while ensuring the shutter maintains contact with the ground during use. You can turn it on and off easily and without any problems. Easy installation: Universal, robust mounting plate with 4 holes, suitable for garden gates, driveway gates, and wooden patio fences, no screws required. "