Product SpecificationName: Caster WheelsMounting Type: V Shaped/U Shaped/H ShapedMaterial: 304 stainless steelDiameter: 48/58/68mmGroove width: 16/22/25mm Product Feature: 360 Degree Rotation, Double Ball Bearing, No Noise Application: Suitable for sliding door wheels, corner rails, slide rails, and round railsPackage Included: 4 x CastersNote▪ Manual measurement, error 1-3mm, depending on the actual situation, please understand.