TOSO Return Fittings 6 pieces [Unused] Loosen the screw on the lace side (window side) of the curtain rail and clamp it. Improves insulation by suppressing cold air in winter and warm air in summer from the sides of the rail ⤴️ I think it has an energy-saving effect. [Please refer to the reference photos] It can also be expected to prevent light leakage from the sides of the rail. ⭐️ If the end cap is screwed on, it may be compatible, but please make your own judgment. The product is in the red circle in the first image. [Curtains and curtain rails are not included] ⭐️ Although it is [unused], it may have been removed from the bag, so please understand. ★ Basically, we ship on weekdays via regular mail, so please understand.