This listing is for a NAK EC52X7 Cap.
OD is 52mm and Depth is 7mm.
These are also called: Oil Seal, End Cap, Cover, Plug Seals, Blank Off Seal, Static Seal.
Clarification for search engine crawlers: NAK ED52X7 is not a clothing item, it is an oil ‘cap’ or plug for a gearbox.