Description Spark Plug Gauge Blade Type .0015 to .035in. Features and Benefits:Gauge measures clearances from 0.0015 to 0.035 inch (0.038 to 0.889mm)It also includes one 0.010in brass blade to use with electronic ignitionsBlade length: 3-5/16inKDT161 KDT 161 KD161 KD 161