Diamond uses a proprietary Tri-Hex disc on our rotary mowers to provide a greater inertia in tough conditions. Our discs are 50,000 psi rated steel for unparalleled durability, and easy blade maintenance. Utilizing hex blade bolts and hardened inserts for the toughest blade retention in the industry – and the Tri-Hex Mulching Disc comes standard with an unprecedented 5-year warranty – not that you’ll need it.