Field cultivator knife with adalloy chromium carbide insert. 3/8" Gas Tube. AK82 Series Knives Apply Nitrogen 3" to 4" Deeper Than Sweeps and Seal Well in All Soils. Adalloy Insert Extends Life 3-5 Times Over Hard-faced Knives. Material Thickness: 7/16” x 1-3/4” x 12-1/2”. Hole Spacing: 1-3/4” to 1-7/8”. Bolt Size: 7/16”. For 3/8" Punched Shanks, Use "Reducer Head" Plow Bolts.