: It is made of zinc alloy and is extremely durable. All curtain rollers can roll and slide smoothly in the track. Lightweight yet sturdy gliders that are easy to slide on. Perfect Size: This metal rail roller measures: Overall width: 18mm; total length: 14mm; pitch: 9 mm. Versatile, perfect for curtains, sheers, decanters, shower curtains. APPROXIMATE DESIGN: The hook is designed to hang on a 360 degree swivel rail suspension, fashionable and classic . Silent wheels are covered with rubber which glides smoothly and quietly and creates a calm and elegant living environment for you EASY AND CONVENIENT - For pleated curtains with needle hooks, simply insert the needle hooks into the eyelet at the bottom of the carrier. For curtains with grommets or loops at the back, just add the hooks. Scope: ideal for attaching curtain panels, room dividers, drapes, curtains and valances . Widely used in windows, closets, bedrooms, offices, restaurants, sliding doors, etc.