Roller Material:Stainless Steel Track Material. Maximum load-bearing capacity of a single door. 330bls (150kg) Suitable for door thickness. From 1.37”to 1.573cm-4cm. The aviation stainless steel. 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, re. According to rail holes. 1 hole need 1 set. Roller Bolt: x4. Door Stopper: x2. T-shape Floor Guide: x1. Install Manual: x1. The picture takes a round-style product as an example, different products have different types of rollers, Please know. How to Choose Track Size. Track’s length should be. Of door panel’s width (like your door width is 2.5FT/76cm, You will need 5FT/152cm Kit for single door).