Combo pack of stainless steel, combination-drive sidewalk bolts and machine screw anchors from The Hillman Group. Hurricane bolts, or sidewalk bolts, are made of strong, durable stainless steel. They are ideal for installing hurricane panels to storefronts and sliding glass doors. Machine screw anchors provide a secure holding point for machine screws. The diameter of the anchor is equal to the size of the screw that fits the anchor.