The Hillman Group 371183 Mushroom Head Spike Anchor, 1/4 x 3-Inch, 50-Pack Product Description The Spike Anchor is a patented, one-piece, tamper-proof anchor for use in concrete, block or stone. The Spike anchor is formed with an "s" shaped configuration at the working end of the anchor to create an expansion mechanism. Since the anchor is pre-expanded, there is no secondary tightening position. From the Manufacturer The Spike anchor is a patented, one-piece, tamper-proof anchor for use in concrete, block, brick or stone. The Spike anchor is formed with an "s" shaped configuration at the working end of the anchor to create an expansion mechanism. Since the anchor is pre-expanded, there is no secondary tightening position. Features One-piece tamper proof anchor Vibration resistant Common applications include pipe hanging, concrete formwork, cable trays and strut Zinc finish offers moderate corrosion resistance Pre-expanded anchor design allows for easy installation 50 pieces per retail package USA SHIPPING estimates delivery times and we work to get your item to you as quickly as possible and within those times, but please know it may take slightly longer than the estimate.