Uxcell a15110600ux0984 Rollerbolt Window Curtain Glider Track Rail Carrier Slide Wheels Rollers 50Pcs Color: white; total size: 22 x 11mm/1" x 0.4"(L*d) Material: plastic; net weight: 36G Package Content: 50(+/-2%) x curtain track rollers; product Name: curtain track roller Bolt size: 4 x 4mm/0.16" x 0.16"(D*l); hole size: 8 x 4.5mm/0.3" x 0.2"(L*max.W) Hole min Width: 4mm/0.16"