Semi-caps have a closed radius that ensures the easy and damage-free insertion of gaskets.

Semi-caps are predominately used for gaskets, cylinder heads, shims, valve, valve guides and bearings.

They are also used for the easy insertion and protection of O-Rings in combustion engines to avoid damage; the closed radius also prevents caps from slipping on the valve.

Semi-caps are also used during insertion of Dunlop, Schrader and Presta tire valves, preventing the valve from damaging the tire itself.