From the Yamaha Website December 20, 2009

"This innovative device offers unprecedented tonal variety and expression for all wind instruments. Using powerful digital processors you can twist and shape your tone for unlimited creativity whether in silent practice, the recording studio, or on-stage performance. The ST5 was designed to work especially well with the Silent Brass Pickup Mutes or with Yamaha's MC7 microphone (or similar microphones). A range of 32 high-resolution digital effects including reverbs, delays, distortion, pitch change, modulation, dynamics and 4-band EQ can be used - up to 6 at a time - to alter and enhance your sound. 50 preset effect programs are provided, and memory for 50 user programs lets you store your own creations. The built-in tuner, metronome with rhythm patterns, and phrase sampler, make the ST5 a powerful practice tool. While inputs for external sources such as recordings allow real-time pitchchange so you can play along with any music."

Specifications:

Effects: 32 (Maximum 6 at a time)
Programs: Preset Programs = 50, User Programs = 50
Power Supply: AC Power Adaptor (PA-D09).
4 AAA Alkaline Batteries equal approx. 9 hours of continuous use (using headphones, backlight OFF).
Dimensions: (W x D x H) 119.5mm x 75.7mm x 26.9mm
(excluding extrusions) (4-11/16" x 3" x 1-1/16")
Weight: 138g (5 oz.) (without batteries)