Kit Description. Potentiometer with switch and regenerative adjustment. DC battery 14500 lithium 3.7 and 9 volt supply, screen voltage 9V. Screen current less than 0.5mA. Filament 2.4 volt supply: 7 pins positive, 1 pin negative, 5 pins empty. Filament current 30mA. Lamp low block illuminated red LED 2.4V supply, current limiting resistor 150 ohms. LED current 16mA. Transformer impedance conversion available after low resistance 8 - 32 ohms headphone listening. No transformer can be used to listen to high resistance 2000 - 4000 ohms headphones. The magnet bar coils need to be wound by yourself! With yarn wrapped and enamelled wire. Suitable for 2P3 case. Case not included! Batteries and speakers () are also not included. Important note: the sound of a single tube machine without an antenna or amplifier is too low! Very impractical! Small amplifier on the phone with input line Bluetooth speakers or computer speakers can be used, the first debugging should be connected! And can only receive a few strong stations, so this kit is only suitable for DIY enthusiasts to play. After the completion of the effect of listening can not be achieved ! Style:Portable Type:FM color:Black Material:plastic Package Contents: 1 x 2P2 electronic tube single light radio board kit Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.