Used to fasten hurricane/storm panels to concrete, block or wood structurals when a non-protruding stud is required. Can be easily adjusted to fine-tune panel attachment. Stainless steel head and Stalgard finish provides outstanding corrosion resistence (withstands 800 - 1000 hours in salt spray testing per ASTM B117 standards). Fastener is drilled and tapped to accept 1/4-20 hardware. Meets TDI and Miami-Dade County hurricane standards.