Martin Seibold Adjustable Spreader

This item comes with very sharp edges (not finished, they cut like a knife) where it should touch the trumpet pipes, and you will destroy the finish. First you need to clear those grose imperfections with sandpaper, and then use it. It may be also very large for some trumpets (it hardly got in place on Yamaha 5335). Very expensive for what it offers. It does make a huge differemce on how the trumpet responds, slotting is much better, but it needs a lot of.work to make.it usable.