The instrument that you see me playing here is the Electronic Valve Instrument (EVI). It is the brainchild of Nyle Steiner, a trumpet player and inventor from Utah. This particular model is one of only two see-through versions that Nyle produced. 

It is a synthesizer for a trumpet player. I found an early version of the instrument in a music store in Chicago in 1979. At the time, I was on the road with Blood Sweat and Tears. The BS&T recording Nuclear Blues a year later contains one of the first commercial recordings of the EVI. Because of its breath control, I think it is the most expressive electronic instrument produced to date. It responds to breath pressure, vibrato, portamento and pitch bend and has a playable range greater than the piano's. It is capable of producing the sounds of many different instruments via the electronic protocol MIDI and is also capable of playing complex new sounds.
When used to control a sampler, the sound palette is virtually limitless. 

A spin-off instrument, the Electronic Wind Instrument (EWI) is a saxophone-style version of the EVI that Nyle produced around 1984. Being easier to play, it is a much more commonly seen instrument. Indeed, the best-known proponent of the EWI was the late famous jazz saxophone virtuoso Michael Brecker. 

NyIe Steiner, the inventor, is an outstanding performer on the instrument. Though you may not have seen him play it, you have undoubtedly heard it, though you may not have recognized the instrument because of the EVI’s chameleon quality. Some better-known films that contain NyIe’s EVI playing are Apocalypse Now, Close Encounters, Dead Poets Society, Fatal Attraction, Ghost, Gorillas In The Mist, Officer And A Gentleman and Witness Escape From L.A. Nyle told me that on Apocalypse Now, almost every melody in the score was played on the EVI. Some tracks were built entirely from overdubs, up to 100 tracks.