Brand New In The Factory Box Racor -30 - 0" HG Vacuum Gauge. This Gauge Will Tell You The Actual Restriction Your Filter Is Adding To The Fuel System So You Can Know When It Is Really Time To Change The Filter. No More Mileage or Hour Change Intervals. A 2 Inch Diameter Stainless Steel Case and 1/8" NPT Brass Back Threaded Gauge.