All the great features that make Innerloc heads the best available and now weve gone one step further by adding the strength of a machined stainless ferrule. That makes the Stainless Extreme 100% stainless..tip, blades and ferrule, all made from the strongest material we can find that still maintains the flex necessary for superior penetration. These heads are small, fast, accurate and DEADLY and since the aluminum ferrule has been replaced with heavier stainless steel, the head carries more energy in a smaller package for unrivaled results on the toughest shots.