You are Buying Brand New And Factory Sealed DIABLO 9 in. 4/6 TPI Demo Demon Bi-Metal Reciprocating Saw Blades for Nail-Embedded Wood Cutting (5-Pack) Model # DS0912BW5.....blade's Full Contact Arched Edge Design with ultra-hardened cutting edge provides faster cuts in fewer passes resulting in less heat build-up to deliver 5X longer cutting performance