the octavider i am trying to locate; is a box the size of a pack of cigarrettes, clips onto your belt. it has a cord that goes to a pick=up which attatches to the side of the mouthpiece and accousticly couples by a small...1/8 in. hole drilled into the mouthpiece. another cord couples the box to a p.a system or instrument amplifier. switches on top the box select a frequency division of 1/2 for trombone-like tone and / or 1/4 for tuba like tone in the '70s i had one ..loaned it out never got it back. Regards to all, Jimmer.