Metric unit 0-30cm on one sides and Imperial unit 0-8 inch on the other sides. Accuracy to 0.1, 0.5mm, other side accuracy is 1/10, 1/16, 1/20, 1/32, 1/50, 1/64 ect. With hole for easily hanging with hook or string. Aluminium Alloy material can be use for long time, good tool to measure .