Since these are the pre-installed runners, remove the side caps at the ends to insert them. TOSO Winpia curtain rail Tachikawa Blind, V17 curtain rail Fits C-shaped rails. The tire diameter is 6 mm. Manufacturer: Tachikawa Blind products Catalog price: 41 per piece The tires on runners wear out over time, making them slide poorly. Why not take this opportunity to replace them? Of course, you can also use them to supplement any missing runners. These are individual pieces, but they are unused.