A single carriage covers Robemaker™ sliding wardrobe doors: a 40mm adjustable sliding door carriage with an acetal roller and a convex steel body. Wardrobe doors are light but get used constantly, and the carriage is the part that goes. The acetal wheel picks up carpet fibre and grit, wears at the convex face, and the door then rubs the frame or comes off its track at one end. The adjuster is what brings the door back square in the opening afterwards. Measure the old wheel across its widest point at 40mm before ordering, because robe carriages are made in several close sizes and the diameter is what separates them. Check too that the track is genuinely convex rather than flat or V-grooved, and that the carriage mounts into the door the same way yours does.