We needed to attach these post bases to a concrete ledge (see pic.), the bennettfastener was the only anchor that could be torqued without any lose from use. We used these fasteners initially to asist in our installation, the nuts for the post bases required acorn style, with the closed end we could not tighten other anchors becuse they rise from the bore hole as they are tightend. The bennett team made us custom product with a shortened thread shaft, we used the cross lines on there filler caps to line up the anchor points. Super clean and solid finished product.