Metallics Combo anchor spring wing toggle bolt features steel construction with zinc chromate finish for superior corrosion resistance. This UNC bolt has thread of size 3/8-Inch and 16 TPI. It measures 4-Inch x 3/8-Inch Dia. Round headed bolt has slotted/Phillips driver. It has drill size of 7/16-Inch and tensile strength of 340 lb for 1/2-Inch wallboard. This bolt is perfect for light-duty anchor for use in hollow block and gypsum wall.