Available now - Aickinstrut vinyl ester bolts. Made entirely of bonded vinyl ester parts (rod and nut). The square heads come standard a 3/8" but can be special ordered at different sizes. Get more info today! Part:375V-125 3/8" x 1-1/4" Vinyl Ester Square Head Bolt, Material: Vinyl Ester, Construction: Head and rod bonded with two part urethane adhesive , Thread Shear: 250 lbs , Torque: 10 ft/lbs.