Accurate Ring Positioning â Provides a fast, consistent way to square piston rings in the cylinder bore, ensuring precise end-gap measurements for engine assembly., Dual-Diameter Fitment â Features two machined diameters allowing use with 3.736" to 3.810" bore sizes, simply flip the tool to match your required fit., Durable Aluminum Construction â Made from strong 6061-T6 anodized aluminum for long service life, smooth operation, and a clean professional appearance., Works With Head Studs Installed â Outer diameter is engineered to clear cylinder head studs, saving time by eliminating the need to remove hardware during measurements., Hollow Center Design â Allows direct visual confirmation that the ring is fully seated and square in the bore, offering far greater accuracy than using a pist.