Genuine Bach Stradivarius Cornet & Trumpet, & others valve stem felts, set of 3.  OD9/16 x ID3/16 x T3/32".  See my item # 273154426055 for a Stradivarius trumpet tune-up kit.  See my item ID# 274172083119 for a set of 12 (dozen).  Fits many, including Bach Cornet, Flugelhorn. Marching Mellophones.  Contact me if you wish to verify your model's fit or you need other parts.