Introduce: A lot of people use small tape measure to have an error zone, think blade hook is loose it is quality problem, actually this is professional industrial design. There are two measurement methods for small tape measure, the first is the top measurement method, the second is the hook measurement method.
The first is the top measurement. First pull out the blade belt, the front end of the blade hook against the measuring object, to measure the inner diameter, the top of the blade hook is zero, read the value vertically.
The second is hook measurement. First, pull out the blade belt, hook the measuring object with the blade hook, and measure the outer diameter.
The inside of the blade hook is zero, and read the value vertically.