The 7F20 is a high-gain twin-triode vacuum tube commonly used as a pre-amplifier in radio and audio amplifier circuits. It has a low internal resistance, making it an ideal choice for use in sensitive amplification applications. Its distinctive “heart” shaped plate gives it an unmistakable appearance and sets it apart from other tubes. The 7F20 is a popular and reliable performer, standing up to rough handling and long-term use, and making it an ideal choice for a variety of audio amplifier, radio and other amplification applications.