This replacement knife is designed for use with the Akiles Diamond 5 Electric Heavy Duty Corner Rounding Machine. The akiles Diamond 5 is designed for high volume corner rounding applications. This die can be used with the Akiles Diamond 5 to round the corners on almost 2" on material at a time. No other corner rounding machine on the market offers this type of cutting capacity. Three radius knife dies are available for the Akiles Diamond 5 (1/8", 1/4" and 3/8").