Size 1 three-sheave deck organizer is designed for leading control lines and halyards neatly across the coach roof and back to the cockpit. Accepts up to 1/2" or 12mm line. Long-lasting anodized aluminium finish. Sheaves made from molded acetal with hollow stainless rivets for easy and tidy fitting. Use 1/4 inch or 6mm flathead fasteners on 43mm centers.