The TrueCut 90° right-angle triangle ruler is perfect for small shapes and pieces! The TrueCut 90° right-angle triangle ruler has specific angles to make cutting shapes a breeze. This is an equilateral triangle perfect for diamonds and other shapes with 60° angles. The TrueCut 90° right-angle triangle ruler works with the patented TrueCut track and guide system for use with the TrueCut cutters, but can also be used with any other rotary cutter on the market. The track and guide system works best when paired with the TrueCut rotary cutters as the TrueCut rotary cutters are equipped with a guide that locks onto the raised edge of the TrueCut ruler. You can use this ruler with any rotary cutter and still love the results it will give you. All TrueCut rulers come with an amazing track and guide system, but they also have easy-to-read marking and are made more durable than traditional rulers. TrueCut rulers are formed with an injection molded thermoplastic that makes the ruler more chip-resistant, flexible, and durable than other rulers.