Material: CARBON STEEL Fastener Diameter (Imperial): 1.5" . Hex-head washer • Mission-style decorative accents enhance the beauty of your outdoor living area • The outdoor accents hex-head washer provides the decorative appearance of a bolted connection • Its design makes for an easier and significantly faster installation compared to through-bolting • This washer and screw combination is designed specifically to fasten outdoor accents post bases, T and L straps, and angles (screws sold separately) • Black finish • 8 pack