The 12BS3A, also known as 12DW4A, is an aluminum-cased power-actuated tube made by Philips. It was used in many early transistor radios as an amplifier, oscillator and detector. It was initially designed for use in car radios and has a tall, thin profile, pin configuration, and base design. The 12BS3A consists of three components: a cathode, a grid and an anode. The anode is connected to the center pin of the tube, with the grid and cathode connected to the two side pins. The three connections are also protected with a metal canister, which can be removed to access the pins. The 12BS3A operates at a wide range of audio-frequency power levels, up to 50 Watts. It is also able to handle high-frequency signals, up to 20kHz, making it suitable for a variety of applications.