Thank you for viewing. This is the HOSCO fingerboard R gauge H-RG1. While the current H-RG2 measures string height in 0.5mm increments, the H-RG1 allows for more precise measurements in 0.2mm increments. It combines 6 different R gauges: 7-1/2", 9-1/2", 10", 12", 14", and 16" into a single gauge. Furthermore, it's not just an R gauge; it also features a scale for measuring string height in 0.2mm increments, making it extremely convenient to use. Made of stainless steel, it can be used for a long time. Thank you for your consideration.