This boost/vacuum gauge is specially engineered to measure vacuum pressure ranging 0-30 in mercury vacuum or 0-20 PSI. These boost gauges provide full 270 degree mechanical sweep which enhances visibility due to the greater sweep of the needle. The bright back lit display enhances night viewing and the aluminum housing reduces its weight. It has a rear twist-on ring mount design which facilitates easy mounting and it has a white dial face. The gauge features either original equipment type electric aircore meter movement or a solid brass mechanical bourdon tube meter movement for better performance and increased accuracy.