1、Laser Engraving Line: Laser engraving line, clear and wear resistant. Constructed from hardened tempered steel with a lube oil coating to prevent pitting and corrosion. 2、Manufacturing Material: Made of high quality spring alloy steel material, strong and durable, which undoubtedly extends its service life. 3、65mn Feeler Gauge Thickness: 65mn feeler gauge thickness, high accuracy, hardening treatment, high hardness, good elasticity, wear resistance, long service time. 4、Easy to Use: Easy to use and fine workmanship. Without any difficult requirements even though you use it for the first time. 5、Wide Application: Suitable for designers, engineers, mechanics to measure the thickness of tappet clearances, spark plugs gaps, bearing clearances, piston ring gaps and other hard to get places.