This new, unique tool enables anyone to cut Crown Molding with no math needed. Just place the tool in any inside corner or around any outside corner and: a. the reciprocal miter saw setting will be the exact angle for the miter saw to cut a perfect miter angle. b. the exact miter and bevel settings for compound angles will be shown in the easy to read windows for 38/52 and 45/45 degree crown slope angle moldings. Roof Pitch measurements and layouts can be made quickly and easily; measure or layout the rise per foot and/or roof pitch by degrees. Common Rafter measurements can be made with clarity and precision; measure and layout Plumb Cuts, Heel or Level cuts and/or Pitch. To support the understanding of the workings of the tool, various diagrams are printed on the tool to illustrate its proper use. The Miter Master Plus is .060" thick, 3-3/4" wide and 10" long. The Miter Master Plus is also available in a 16" size and can be purchased on Amazon, ASIN B0001NM0KZ4.