The material of hanger is stainless steel, rail is made of high quality space aluminum nickel plating. Effective waterproof and rust-proof for long time use. Max Door weight capacity is 220 lbs. Adjustable roller screws fit Door Thickness from 1.37″-1.57″(35-40mm). Unique upgrade spring damping door stopper makes no sounds when opening and closing doors, minimize the impact to track. The keel in the track make the structure more stronger. Adjustable wall attachment can match any distance hole stud. Intimate 24-hour online customer service. Ngle Door Track Kit. 2 PC (1 PAIR). 4 PC (2 PAIR). How to Choose the Correct Track Size? Door Min Track Size= 2 × Single Door panel Width. Example: For a 36″/3FT door, recommend you choose a 72″/6FT track at least. Door Min Track Size= 4 × Single Door panel Width. Example: For a 36″/3FT door, recommend you choose a 144″/12FT track at least. Tip: If you have enough space you can also choose the longer track size. The aviation aluminum track with decorative chrome plating, wall thickness is up to 2mm. The track adopts mechanical design, add keel support in the middle, through strict test can strongly support weight. Add anti-falling wheel on the roller. Can effectively prevent the roller hanger from falling off during sliding. The head of the door stopper is nylon arc. Perfect fit with roller pulley radian, reducing noise.