1. When the fiber optic visual fault locator laser is very bright, but there are signs of looseness when the fiber jumper is inserted, the red light cannot be injected into the optical fiber, and no light can be seen at the other end of the optical fiber, it means that the ceramic sleeve is damaged and needs to be replaced with a new one. 2. Autonomous replacement, saving time and effort 3. Applicable to: fiber optic visual fault locator, optical power meter, pda red light all-in-one machine, etc. 4. Most of the ceramic cores used in red light pens are 7mm. If you are not sure, you can consult the original instrument manufacturer or buy a (5mm+7mm) ceramic package and try it back. There is only one type of metal head. Please confirm clearly before purchasing. 5. Product material: ceramic /metal
