Keely EC BOSS SD1 Modify, like new, using germanium transistors, low noise, for sale. It has been stored as is, in deadstock condition. As it's an early model, the parts used are good (see the manual). I fell in love with the sound pressure and low noise, and bought it new from a major musical instrument store about 10 years ago. The BOSS SD-1 provides overdrive effects and is adjustable with 3 knobs. - Model Name: SD-1 - Color: Yellow - Function: Overdrive - Number of Knobs: 3 - Distributor Name: Tahara inc. Thank you for looking.