This is the same Rose-Index everyone knows and loves, but with an add-on called the Degree Wheel. The degree wheel is an add on of laser markings showing 360 degrees. Lining up is as simple as pushing a machinist square into the vee grooved side of the Rose-Index. As you push the Rose-Index into the part it will become aligned with the 0 degrees up and 180 down. We recommend that you only leave a few thou of stock protruding from the Rose-Index. This will protect you from scratching the face of the Degree Wheel because the machinist square will be in contact with the stock. Choose the degree of rotation you want. If you want a 10 degree rotation simply line up the 10 degree marks on the top and the 190 degree on the bottom. Simply add 180 degrees to your desired angle, and line up the desired marks on the square.