One Of The Single Most Important Factors In Determining How Your Engine Performs (And How Long It Performs Between Rebuilds) Is Proper Oil Temperature During Operation. Knowing Your Exact Temp Allows You To Make Sure Youve Got The Proper Oil Weight And Cooling Capacity. Utilizing Autometers Ultra Precise Bourdon Tube Meter Movement, You Can Be Assured Of The Most Accurate Possible Readings Of The Life Blood Of Your Engine. A 6″ Capillary Tube And 1/2″ Npt Mounting Nut Are Included.