About 11,20,00,000 results (0.45 seconds) Search ResultsFeatured snippet from the webJ Bolts, or Hook Bolts, are typically used for roofing applications. They host a hooked bottom which is designed to hook onto rebar embedded in concrete and threading on the top of the fastener. They are a very common and durable fastener used by construction workers when erecting a new building and also used in solar structures.