No deviation from the track: Installing our olive rail can help your gate stay on track when opening and closing manually or sliding the gate electrically, thanks to the "extended" nylon rollers mounted on the axle, which rolls by itself and allows your gate to slide. Material: This nylon swivel caster is made of nylon with a very strong and dense structure, stable performance and long service life. The structure includes: An internal body and a nylon tread for smooth rotation. Nylon is a strong material that resists impact, abrasion, high and low temperatures. It is also resistant to chemicals. It is the best substitute for wheels when they are worn or damaged. Suitable for electric doors, sliding doors, etc. Good Performance: Our nylon olive guide is made of sturdy steel with strong bearing capacity, good elasticity, high toughness, no deformation, wear-resistant, corrosion-resistant and so on. The outer surface of the bearing is smooth, which can reduce the noise generated by the sliding friction of the iron door. It can be used indoors and outdoors.