Indicator base is a sturdy billet alum. design with a 0 to 1.00" indicator that reads in .001" of an inch. Indicator base has three positions so the engine builder can move the indicator to check different parts of the piston. One hole is moved over .825" from center and the other hole is moved over 1.650". Thumb screw is simple to turn remove indicator over to desired hole drop it in and let the fun begin.
TDC base is 6.875" long, 1.50" tall and 1.50" wide. Cutout on the bottom side is 5.375" wide and .700" deep. Base is anodized black and will provide years of service and many engines built.