Abstract: A clamp apparatus for selectively occluding a resilient tube to prevent free flow of fluid in the tube. The device comprises a base member to which the resilient IV tube is attached or through which it passes, and a slide clamp that slides relative to the base member and relative to the tube. The aperture in the slide clamp has a relatively open hole at one end, through which the tube passes when the slide clamp is an open position, allowing fluid to flow through the tube. The aperture also has a relatively constricted slot at the other end, through which the tube passes when the slide clamp is in the occluding position, preventing fluid flow through the tube. The slide clamp includes a groove for receiving a cooperatively shaped rib on the base member. The groove and rib are configured to guide relative movement between the slide clamp and the base so as to prevent significant lateral movement.