Description: 1. Ceramic core, suitable for most red pens, such as letter red pen, small red pen, metal, plastic, pen, etc. 2. Ceramic core / ceramic sleeve / fiber optic pen ceramic core / red pen tip ceramic tube 3. Installation method: Rotate counterclockwise, remove the metal head at the front end of the red pen, remove the ceramic tube with tweezers or needle-nosed pliers, and gently insert the new ceramic sleeve by hand. Remember to install it without force. Put it in place, replace the metal head, use a needle-nose pliers to pad several layers of paper, tighten the appropriate force 4. Frequently Asked Questions: The red pen is not bright, the light is not afraid, and it may be scrapped because the red ceramic pen is broken. When the red pen is very bright, but the red light cannot be injected into the fiber, and the connection is fast When the device is inserted into the stylus, the gap is too large. When it is shaken, your ceramic sleeve has been damaged and needs to be replaced. Package Includes:(8 Pack) 1Pcs 7mm Ceramic sleeve Tube