Features: Each package contains a pair of fully tested and matched 6K4 Vacuum Tubes. Replacement for 7-pin 5654 or 6AK5 or 6AK5W or 6Zh1P or 6J1 or 6J1P tubes. It can directly replace WE-403A or 403B or EF95 and ordinary 5654. And can be used for the device that comes with 6J2 or 6J3 or 6J4 or 6J5 or 6K5 as a replacement. These 6K4 tubes show you the difference in natural voice reproduction and simple musical. They sound more clear with an emphasis on clarity, larger soundstage, and bass response is more noticeable. Hear the difference, enjoy your music. High reliability and stability. HiFi and soft sound, low noise. It is fuller, wider soundstage. The treble is smoother and bass is clearer and more pronounced while more complex music was more defined. Note: Replacing the wrong type of tube may damage your amplifier. If you are not sure this 6K4 can be used as a replacement for your audio device, please check with your amplifier manufacturer. Specifications: Model: 6K4 Type: Electronic Tube Material: Glass, Metal Color: Transparent Quantity: 2pcs Package Size: 7.5x5.5x2.5cm or 3.0x2.2x1.0in Package Weight: 30g or 1.1oz Package List: 2 x Electronic Tube Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement.