The Pierobon Deep British Cornet mouthpiece is one of the signature line of Marco Pierobon of the Gomalan Brass.
The rim diameter is slightly smaller than a Bach 5C with a wide Gabriel style rim. The rim has an ID of .662 and an OD of 1.12. The lateral dip is 15/1000". This is the same rim found on the Pierobon C, Lead , Pierobon British cornet mouthpiece (which has a shallower Wick B cup depth) and Pierobon Flugel.
The cup of the Deep model is the depth of a Wick 4 cornet mouthpiece and the throat is #15.