The Endura 4 Lightweight with a blade crafted from K390 K390 MICROCLEAN is a state-of-the-art cold work tool steel produced by the particle metallurgy process. Its advanced alloy mix was specifically developed to provide the extreme wear resistance and high compressive strength needed in industrial cutting blanking and punching operations. Despite its toughness its exceptionally fine homogeneous microstructure also makes it readily machinable and easy to heat treat.