RUKO 1 per box, 6-5/16" diameter by 1-2/3", High Speed Steel Bi-Metal Hole Saw, red. Bi-metal H.S.S. Hole Saw with varied toothing ensures a even cut and requires less effort, High rotational precision. Sturdy body construction. Positive chipping and cutting angles ensure more aggressive and faster cutting. The reduction in vibration and heat development during cutting achieves up to three times the tool life. (106160)