:: Three-Piece :: Three-piece tip assemblies are the most common type of shut-off valve. They tend to be either free-flow or locking-ring in design. The locking-ring design has “tabs” on the ring, which cause the check ring to rotate with the screw. It is important to check the ring travel when a very short stroke length is required. Concor will design a “Precise Metering” tip assembly in such cases.