Contains: Sixteen – 4″ x 1/2″ blades with thicknesses .005, .006, .007, .008, .009, .010, .011, .012, .013, .014, .015, .016, .017, .018, .019, .020 Blades have 1″ 45O offset for checking valve clearances For ignition and general purpose measuring The sizes, both decimal and metric equivalent, are permanently etched on each blade.