Oil Pressure Gauges › M8 to -3 Case Fitting for Oil Pressure Gauge or Turbo Image 1 of 1 M8 to -3 Case Fitting for Oil Pressure Gauge or Turbo $12.95 Case fitting for the do it yourselfer who wants to tap into his oil galley and run his own gauge or feed a turbo Add To Cart Added! Case fitting for the do it yourselfer who wants to tap into his oil galley and run his own gauge or feed a turbo