Metal Smooth Bearing: The lower wheel uses a more stable and heavier metal bearing. The concave wheel design is more uniform, the bearing shaft is smooth and round, and the sliding has no scratches. High quality material: Stainless steel plate, thickened plate thickness up to 1.5mm, thick material, not easy to deform, can be used in humid environment, durable and rust-resistant. Close cleaning function : Each activity automatically cleans dust deposits and stagnates, effectively preventing dust from entering and increasing durability. Suitable for kitchen cabinets and cabinets of different styles. Simple structure: Quick assembly knob, upper guide wheel adopts copper knob, retractable upper wheel is convenient for door leaf mounting. Cylindrical catheter, horizontal rotation structure, slides smoothly without jamming. Package includes: 2 sets of sliding door wheel sets can form two pulleys. It is recommended to install 2 to 4 pulleys per cabinet door.