Features: Each package contains a pair of fully tested and matched 6K4 Vacuum Tubes. Replacement for 7-pin 5654/6AK5/6AK5W/6Zh1P/6J1/6J1P tubes. It can directly replace WE-403A/403B/EF95 and ordinary 5654. And can be used for the device that comes with 6J2/6J3/6J4/6J5/6K5 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: , Metal Color: Transparent Quantity: 2pcs Package Size: 7.5*5.5*2.5cm / 3.0*2.2*1.0in Package Weight: 30g / 1.1oz Package List: 2 * Electronic Tube