JEGS digital compression gauge takes the guesswork, inaccuracy and inconsistency away from dial type gauges. Consistent to within +/- 1%, repeatability of +/- 0.1% and displays in tenth pound increments from 0-300 PSI. Features automatic shutoff and zeroing with push button manual pressure relief valve, on/off and reset functions. Includes battery, rubber shock cover with 14mm short, 14mm long and 18mm short spark plug adapters and a handy storage case.