Detail: 
• A small amplifier circuit that used for amplifying signal from various noise sources and sending out through earphones for a clearer sound. 
• Power supply: 3 VDC,
• Consumption: 60 mA. max.
• Output power: 1+1 W. max. stereo.
• Adjust sound level with trimmer potentiometer.
• S/N ratio: 70 dB (A weighted)
• Sensitivity (1 kHz/500 mW): 120 mV. eff.
• PCB dimensions: 2.24 x 1.34 in.
• Recommended housing: Future Box (FB03)