From Jeff Sheets website
Model: VIP Forged Irons
Material/Mfg: Billet Forged 1020 Carbon Steel 100% CNC Milled Cavities
The legendary VIP irons became the first iron model that Bill Totten oversaw the design work on with help from his teammate David Cersley and an overall design guidance from Golfsmith’s Brandon Ortwein. Kudos to a great looking set. The heads are forged out of a soft 1020 carbon steel with the cavities 100% CNC milled for precise geometric layout, face thicknesses and weight distribution.