McMaster 97110A622 Galvanized Steel Wedge Anchors for Concrete, 1/2" Diameter, 3-3/4" Long, Pack of 25

Secure junction boxes, safety railings, and structural beams in concrete floors. These anchors have a wedge-shaped base that expands against the hole’s sides, forming a tight grip that withstands high pull-out forces. Since the grip is focused at the base, these anchors are best suited for concrete, which can handle the gripping pressure better than softer block and brick. However, they require holes that match the anchors' diameter exactly to achieve their pull-out strength, making them more difficult to install than sleeve anchors.

To install, drive the anchor through your component into a drilled hole until the washer and nut meet the surface. Then, tighten the nut to expand the anchor base. Remove your component by unfastening the nut, but the anchor itself cannot be removed.

Corrosion-Resistant Galvanized Steel—Combine the strength of steel with the rust resistance of stainless steel. These anchors are an economical alternative to 18-8 stainless steel in wet and outdoor environments, but they’ll corrode or pit when exposed to salt water and chemicals.