One piece backbores are all regular weight. They are a great choice for players who do not want the option to use different shanks for gap adjustment or C trumpet.
Small - Slightly larger than Schilke A backbore. Produces a compact lead sound with good upper register support.
Medium - Similar to Warburton 7 or GR #2 backbore.
Medium-Large - Similar to Bach 10 backbore. This is an excellent all round backbore suitable for orchestral playing.
Well crafted and free blowing. I like it.