*Thread shear values shown represent a 3:1 safety factor. Vinyl ester square head bolts are used for concrete mounting and general purpose fastening applications. The square head bolts are constructed from vinyl ester all-thread rod and vinyl ester square nuts. The units are bonded together with a durable two part urethane adhesive. The square head bolts are offered in 3/8" diameter but can be supplied in other diameters as a special order. Contact the factory for pricing and availability of special diameter square head bolts.