Replacement thumb-clamp for the Urocare® Straight-Thru Adadptor with Thumb Clamp. Provides an easy on/off flow control/closure. It allows either a free-flow (On) or complete restriction (off) of fluids passing through latex, silicone or white-rubber tubing 0.38″ O.D. (0.95cm Ø) or less. It is not recommended for clear-vinyl tubing as this type of tubing tends to be more rigid that those listed and may not hold.