This is a replacement guide roller (the rollers on the sides) for the carriage of the PPS Deluxe Reformer used in Peak Pilates (not original). This is a set of 4 (4 are used on the carriage, front, back, left, and right). The PPS Deluxe Reformer often has problems with the resin parts of the guide rollers deteriorating over time (see the last photo for reference. They are yellowed and damaged. I haven't confirmed it, but it's possible that MVe reformers use the same rollers). The original guide rollers have a diameter of 38mm, but I couldn't find any 38mm ones in Japan, so I was using 35mm ones. I was finally able to find the same size and purchase them from overseas. I actually replaced them, and there is no looseness or play with these products. The only difference in dimensions from the original is the thickness (the original is 11mm thick, but this one is 10mm thick. There is no difference in use). Purchasing through a distributor would be more expensive, and even if only one is damaged, the others will eventually deteriorate over time, so I am only selling them as a set of 4. Also, it can take nearly a month to order these products, so if you are using them in a studio, I recommend having spares. Please ask if you have any questions about installation.