These heavy duty combine-cultivator points are manufactured from high grade carbon steel.Zone hardening provides maximum hardness without breakage at the critical neck area.Protective dimple protects bolt head.Bolt hole is 7/16" inch and adapts to old 3/8" inch machines with our step head bolts. Four popular sizes from 4 to 7 inch widths (100 to 175mm).Bolts to suit these points are listed above.Image of chisel plough is for reference purposes only.