This is a set of 4 silicone tubes for replacing the rollers of Fujitsu ScanSnap S1500 and similar scanners. Outer diameter: 12mm, Inner diameter: 6mm, Length: approximately 24mm. Carefully pull and rotate the drive belt, then gradually remove the deteriorated rollers. Making a vertical cut in the new tube and fitting it over the roller will restore the feed function. Disassembly is not required. You can easily do this by referring to YouTube for instructions.