Specifically designed to simplify takeoffs from architectural and engineering drawings, the scale master pro finds linear measurements of any shape as well as rectangular areas and volumes and it converts between scales and dimensions. It comes with 72 built-in scales (39 US and 33 metric for maximum versatility). It also features six custom scales (three each for US and metric units), enabling you to define any scale, even from plans that have been reduced, enlarged or are just out of scale. You can easily store the new scale permanently into the device for future use. Other features include two built-in memories, dedicated length, width and height keys; push-button counter to keep track of items while rolling; switch for locking in mode, scale and units while rolling; and a subtract key that allows you to deduct rolled distances. Easy to learn and use, the Scale Master Pro will save you time and reduce errors on your estimates and bids.