Two stops are used as clamps to fix a cleat, block, or other piece of hardware to the mast without drilling holes. This technique is often used to install components of a downhaul or cunningham. A 10-25 fastener passes through the cleat and into the female thread of the stop. The stops are placed into the mast track and the cleat is placed outside of the track. When you tighten the fastener, the cleat is clamped to the mast.

We also have a similar part equipped with a stud and large knurled knob for use without tools (see "May we also suggest" below) for use when the position is changed frequently.