Front side is Heavy Hex Inches. The back side is Heavy Hex Metric.
It measures both the stud and nut sizes
Introducing the High Heat HexSizer® - the ultimate tool for identifying nut and bolt sizes in high-heat environments. With the ability to withstand temperatures up to 1200°f/649°c, this tool is perfect for steamfitters and those working on live process units, heat exchangers, insulated piping, and more.
Made from durable 6061 aluminum, the HexSizer is anodized blue and laser engraved for added resilience. The clear sheath packaging also includes a detachable black tether for easy carrying on the job. Say goodbye to guessing and frustration, and hello to quick and accurate nut and bolt identification with the HexSizer. It's a must-have tool for any Professional Bolting Technician.