Rule / Measuring Tape

when people want to draw a circle or arc ,they most use Compass,but sometimes crafts or Engineering need draw
a big circle or arc,there are not have big compass."Rule" is mix measuring Tape and compass ,also have a pen ,Bottom is
use rubber to let the center of a circle can fix. When you need draw a circle or arc,first is adjust the size,then push the Button to Fix the size,after this
you can draw a Circle or Arc you want.