CONVENIENT TO MEASURE: Made of stainless steel, small size and lightweight, easy to carry. Simply structure, convenient to measure. You can place the gauge on a hole and read the measured value. ACCURATE RULER SCALE: Accurate numbers and increments are etched into the surface, easy to read. DIFFERENT GAUGES: There are several different gauges in one set that can meet your different needs. APPLICATION: Suitable for inner diameter measurement, aperture measurement, groove diameter, etc.