Also known as double expansion anchors, these expand from both sides for full contact with your hole’s walls. They’re often used to mount handrails, shelving, and light fixtures. Since the gripping force is distributed along the entire length of the anchor, it won’t crack soft materials like block and brick. You can use these anchors as an alternative to drop-in anchors in concrete near edges, corners, or other weak points, but they are not as strong.

To install, hammer into a drilled hole and position your component. Then, insert a screw or threaded rod and tighten. For maximum expansion, the anchor should protrude slightly above the surface before threading the screw. All create a permanent female-threaded connection that lets you remove and reinstall a screw or threaded rod. They cannot be used in overhead applications.