... battery power,echo 4.ISO 9001,FCC,CE,Rohs 5.transistor:3035 high power Educational Equipment for Schools/Amplifier Function:1 ... comes with 6V DC power supply.8.it uses toshiba transistor.with high power output.This fits your indoor activities. You ... : it is teaching amplifier, pa amplifier, uses high power amplifier transistor, famous name of Toshiba. it is popular and affordable but ...