I can't believe I've never had these before! it makes cutting floor boards so much easier, around doorways especially it's normally hard to get a tight fit with all the angles, but having this gauge enables me to trace exactly the shape I need onto the board. They are pretty stiff, but that means it holds its shape. there appears to be an adjustment screw for the tightness but I haven't had to use it yet. I can't stress enough how much time and mental anguish this saves me!