Shower Curtain Roller Rings, Shower Curtain Hooks. Glides smoothly, quietly & effortlessly along shower rods. Prevents tears in curtain liners. Imagine no more tugging at the shower curtain. Our ROLLER BALL Shower Rings have 6 BALL BEARINGS on the top to prevent SCRATCHING the rod. Unlike our competition that sells them with 5 or less ball bearings. Made of nickel plated brass. Set of 12. Measures 2 3/4 in. H to fit standard shower curtain rods.