The S & S Cycle Replacement 3-5/8in. Bore Piston Rings are specifically designed for S&S Pistons, with a piston diameter of 1-1/2mm. Made of durable aluminum alloy, these piston rings come in a set of 10 and are manufactured in the United States by the trusted brand S&S Cycle. These piston rings are a reliable option for maintaining and repairing engines with a 4-stroke design, ensuring quality performance and longevity.