【Product Name】 ★ Mark Curry Heavy Bottom Cap (Magnum) for Yamaha Trumpet - 1 piece 【Description】 ★ This part was purchased new from an authorized online retailer in Japan. ★ The package has both YAMAHA and STOMVI markings, but I don't own a STOMVI trumpet, so I'm unsure if it's compatible. ★ It fits YAMAHA current models 3335 and 4335GII. ★ Weight is approximately 54.4 grams. ★ My impression after testing it was that it provided moderate resistance, resulting in a fuller sound and improved playing feel (this is just my personal opinion). ★ Although it's a bottom cap for Yamaha trumpets, I'm not sure if it fits all Yamaha trumpets depending on the model number and year. Please be aware that I cannot offer a refund if you damage the threads or the instrument itself by forcing it on; this is at your own risk. ★ I will ship it quickly and carefully via Japan Post.