※ Please carefully measure the ring size of your guide. If the size is different, you won't be able to install it. If you can confirm the guide's model number, you'll know the required size. I am selling rings in 4mm, 5mm, 5.5mm, 6mm, 7mm, 8mm, 10mm, and 12mm sizes, so if you are looking for a different size, please search from the list of my items. These are SiC (Silicon Carbide) rings. Please use them to repair broken guides. They can be installed on guides with a 5mm diameter ring contact surface on the frame. Here's how to install them: 1. Prepare the guide frame. Sand and clean the ring contact surface of the frame beforehand. 2. As shown in the third photo, place the ring vertically and try to see if it passes through to the other side. It's ideal if it goes through with a little pressure. If it doesn't go through, use a file to widen the contact surface by sanding the frame. 3. Insert the ring into the frame. If it's tight, use protected pliers to gently crush it and insert it. (Photo 4) 4. Apply adhesive to the border between the ring and the frame. Epoxy adhesive, which has a longer working time, is more suitable than instant adhesive. Apply the adhesive with the tip of a needle or toothpick, tracing the outer circumference of the ring on both the back and front surfaces. A thin layer of adhesive is sufficient. Be careful as the ring can break if it receives a strong impact. It breaks easily with a "crack" sound, so be careful when inserting it with pliers. It comes in a set of 3 in case of failure. Although the adhesive strength will be lower, it is also an option to sand the frame more and insert it loosely. If you use epoxy adhesive, it won't come off easily, so you don't have to be too concerned about perfection. If you do it well, you can convert inexpensive guides to SiC guides. If you are interested, please give it a try. This is a special item, so please ask if you have any questions.