See the invisiable / tool

When we seam buttons,we can't see buttonhole from the opposite side cause the clothes cover it, so very often we pricking our fingers .”See the Invisiable” is designed to solve this problem . Fix the button in the round-shaped hollow-out,in this way,the needle can accurately go through the buttonhole and won't pricking the fingers.
“See the invisible”has 7 types to meet the needs of different size of buttons.