Welding gauges are a measuring instrument used for all measurements during welding work. Most of the materials used are stainless steel that does not easily rust, and the gauges required for measurement are typically integrated, but there are also single products such as groove gauges. The shape varies depending on the product, but the size that fits in a pocket is common. Some products include dial gauges. Examples of usage before welding include measuring plate thickness and groove angle, measuring root spacing and root face height, etc. After welding, the fillet weld, throat thickness, and leg length can be measured to confirm that the welding conditions are met. Depending on the product, those that can measure the undercut depth can be selected. Since the measuring range varies depending on the model, select the product according to the application.