The Seneca Woodworking Imperial Thickness Gauge for the Domino DF500 allows you to quickly and effortlessly adjust the Domino fence offset to center your mortise on a variety of imperial material thicknesses. The gauge installs in less than a minute using a Torx T10 bit (not included), and is a direct replacement for the metric thickness gauge included with your Domino DF500.The Imperial Thickness Gauge is CNC machined from Delrin material and designed to center on 1/2in., 5/8in., 3/4in., 7/8in., 1in., and 1-1/8in. nominal ply thicknesses.We currently offer two products to create the correct offset for mortising imperial lumber. The Domiplate and the Imperial Thickness Gauge. If you primarily work in only 1/2 and 3/4in. material, The Domiplate is probably the right choice because it provides a reliable way to set a specific offset and create many mortises with absolutely no possibility of in.Fence driftin.. On the other hand, If you frequently use material other than 1/2in. and 3/4in., the new thickness gauge allows you more versatility in choosing different fence offsets. However, it doesn't provide that extra in.insurancein. against fence drift that the Domiplate offers.