Electronics-Salon Battery Supply Audio Mono Amplifier Kit, NJM386D, LM386 Low voltage audio power amplifier module, based on NJM386D ( LM386 ) IC design. Voltage Gain : JP1 Open 26dB, JP1 Close 46 dB. Input Resistance : 10K ohm (Volume Max.) Operating Power Supply Voltage : DC 4 - 12V. PCB Size : 50 x 32 mm ( 1.97 x 1.26 inch ) PCB Thickness : 1.6mm ( 0.063 inch ) Maximum Height : 24mm ( 0.95 inch )