Product Descriptions Fitment: Offset valve tappet gauge tool is a wide range of professional automotive-specific tools designed to measure the gap between the valve tappet and the valve stem of internal combustion engines Features: 1) A308 tool set consists of 11 gauges of various sizes to choose the appropriate blades for the intake and exhaust setup, each gauge has an offset tip to allow the user to access and measure the clearance between the valve stem and tappet in tight spaces .