Fig. 23 shows a saw which is known as a back saw, probably because of the extra piece on the back which limits the depth to which the saw will cut. It is also called a "tenon saw." There are a number of different kinds, varying in the width of the blade and in the length of the saw, and they are used for various special purposes, usually in miter boxes and for sawing bevels on moldings. Fig. 24 shows the arrangement of the teeth on a back saw. It will be seen that the front of the tooth is nearly straight, and that the slope of the back is very sharp, making the number of teeth to the inch more than in the rip or cross-cut saws.