This classic styled vacuum gauge from Smiths is electrically operated via a sender unit which provides more reliable and accurate readings than traditional mechanical gauges.Highlights loss of vacuum pinpointing potential engine issuesCan be used as an economy gauge to improve MPGElectronic operation for more accurate readings52mm diameter fits most mounts or podsMulti coloured scale for easy readingRetro looks to suit classic dashboardsVacuum gauges measure the amount of vacuum produced at the inlet manifold or plenum chamber. A drop in vacuum can highlight issues such as split or loose air hoses, loose manifolds or faulty gaskets. They can also be used as a economy meter as the more vacuum created translates to more fuel being used so you can use the gauge to alter your driving for better MPGs. The gauge features an easy to read multi colour scale and a classic chrome bezel.A Smiths sender unit (part number PTTR2300-03-8NKIT) is required for the gauge to operate.