Rebco Collar Stops are wireline-set mechanical stops designed to seat and lock in a tubing collar recess, providing a positive, depth-referenced landing point in the wellbore. Once set at the collar, the stop serves as a physical platform for positioning, setting, or activating downhole tools. Collar stops are primarily used to provide a controlled, known depth reference for operations that require a tool to be held stationary at a precise elevation, such as when setting a wireline-conveyed plug, packer, or valve at a location relative to a known collar. The stop is set by jarring down to lock the collet fingers into the collar groove, and retrieved by jarring upward to disengage. Available with threaded connections and in multiple OD ranges to suit all standard tubing sizes.