The Qualcraft shingle shark is designed to allow for accurate and repeatable cuts at any angle as well as lengthwise cuts for a starter course used along the edge of the roof. It has two offset holes one for America and one for US shingles. The crosscut guide adjusts a full 180 degrees for any angle cuts face up or face down and from either the top or bottom edge. It can be set up by using a cleat to prevent slippage using a piece of two-by-ten lumber and footing the tool against it or by using a 6 In. x 90-degree roof bracket.