Thank you for viewing. The product is a "Finger Rest for PJ Bass". By adding a raised area to the part corresponding to the 5th string of a 5-string bass, your finger will hit and stop when playing the 4th string, allowing for stable playing. The space for the right-hand thumb is also larger, providing stability, and you can switch from a 5-string bass without any discomfort. The size is: 63mm between the F.PU and R.PU 13.2mm for the finger rest part It is made with a 3D printer, and the material is PLA. Unlike general plastics, the surface is not smooth and has small bumps. Thank you for your understanding. ※This product comes with super-strong double-sided tape. It is not compatible with lacquer paint. Please be aware that it may leave marks on other delicate paints as well. Thank you for your consideration.