The one and only Thunderboltâ„¢ is the original self-tapping anchor with the power to be used on a whole range of construction materials including concrete, brick and stone. It is a one-piece, non-expansion anchor, meaning that it does not require a wall plug or resin, and therefore makes it ideal for close to edge fixing applications. The threaded anchor and self-tapping action allow for safe anchorage, with the substrate becoming the nut to the bolt.