These are Socket Head Sheet Metal Screws by DU-BRO.
Steel construction. Coarse threads designed to grab onto relatively thin sheet metal. Cap head with a hex drive insert. Uses a 3/32" ball driver (BONR1020).
SPECS:Length: 1" (25mm) Diameter: 4mm kr3/23/05 ir/jxs BOX DIMENSIONS: 2.25" W. X .25" H. X 2.25" L. BOX WEIGHT: .02 LBS.