They are an interference fit with the BB, and will require proprietary Phil Wood BB installation tool to install. Cups comes with a small tube of retaining compound.
We offer bottom bracket cups in these sizes: British, Italian and French.
Cutting taps used to produce the bottom bracket thread in cups leave microscopic hairs and cracks in the thread form. Thread in PW cups is hand polish to all but eliminate galling between cups and the bottom bracket thread.
All cups are sold as a set and include thread retaining compound (which must be used during assembly).