This is a holder to mount a 52mm gauge to your dashboard. Two mounts are included, one curved for steering column or pillar mount, and one flat for dashboard mounts The original holder I printed had a 52mm aperture which proved too small and required sanding back the inside to actually fit the gauge inside. This model has a 53mm aperture so hopefully it is an easier fit. If the gauge is too loose just wrap some tape around it to increase its diameter. A small nut and bolt are required for assembly, which is also used to adjust the tilt angle. The mounts have a cut out for a nut with 4mm sides - assemble the gauge holder and when you tighten the bolt the nut should be pulled into the cut out for a nice secure fit. My application was a 52mm Turbosmart boost gauge screwed onto the steering column of a 2002 WRX. Printed on an UP Plus in ABS with supports and spray painted.