I've also found times when thin cloth measuring tape is easier to use (when measuring distances for decal placement) than either roll up metal tape or a stiff ruler. I'll add that my angle piece can also be used to find and mark the front center of the seat tube as well as the top of the down tube for decal placement using the point of the lugs and water bottle bosses. For example the bottom of the seat lug and the point of a bottom bracket shell (if it has a point) can be where one end of the angle iron is placed and the other end used to make a pencil mark where it comes in contact with your placed masking tape. Of course you have to do this on both sides in case the points are off a bit.