The APR Boost Gauge utilizes a VDO boost gauge contained in a vent-replacement pod. The pod was designed on the computer with Pro-E for the best in fit and finish and is injection molded in plastic, giving you factory-like look and feel. The gauge itself is a 52mm mechanical VDO gauge giving very accurate and reliable boost and vacuum readings. It reads from 30 in. Hg of vacuum to 25psi of boost. For higher boost systems, a 0-30psi gauge without vacuum reading is available.