Installation in a carbon mast for the main halyard, because the pure carbon fiber will eventually damage the halyard sheath when manually hoisting the mainsail on the mast.
The installation width for the 10mm version is 14mm, the length 80mm if the hole at the top of the mast is rectangular; for a curved hole, the length will be correspondingly greater.
And only 10mm will actually fit through the slot. If you have an eye splice at the end of the halyard, you might not be able to thread it through...