Sold as one unit. (1 unit = Bx/20.) Hex head. Grade 5. Vibration resistant. Anchor Size, Drill Size (Shown below). Min imbed 1/4= 1-1/4", 3/8 = 2", 1/2 = 2-1/2", 5/8 =2-3/4", 3/4 = 3". Zinc plated steel. Boxed. 3/8"x2-1/4", 3/8". Manufacturer number: 370834. SKU #: 78696. Country of origin: China. Distributed by Hillman Group Rsc.