The LENOX 9 in Demolition Bi-Metal Reciprocating Saw Blades with Power Blast Technology refer to a high speed blasting process known as peening, which is applied to the tang and cutting edge of LENOX Bi-Metal Reciprocating Saw Blades to reduce breaks and increase durability. The process is commonly used in the aerospace and automotive industries to strengthen steel and has been used in manufacturing LENOX Band Saw blades for years. By blasting the cutting edge and tang of the blade, a layer of compressive stress is created on the surface of the blade in the areas that receive the most abuse. This compressive stress reduces the formation of cracks which causes blade failure.