werner mega-swivel steel anchor is a robust anchorage bolt for use in concrete applications. The bolt requires a pre-drilled hole of 3/4 and 4.5 depth in 3000 psi concrete with minimum concrete thickness of 5. The d-ring swivel provides a full range of motion at the anchorage. features: robust steel design with 360 swivel of the forged d-ring drill hole of 3/4 with 4.5 depth minimum 3000 psi concrete and 5 thickness