The Lenox Speed Slot Bi-Metal Hole Saw with T3 Technology has enhanced tooth geometry that cuts 50 percent faster than previous Lenox hole saws. Twice as durable as our previous generation when cutting through metal, this bi-metal hole saw features thicker walls to minimize tooth loss and improve durability. A staircase Speed Slot has a wide slot placed low on the hole saw and multiple leverage points to make it easy to work plugs out with a screwdriver. This design effectively removes sawdust, chips, and helps prevent plugs from becoming stuck in the saw.