1)Business Type: Manufacture and sale 2)Outside Diameter: 25mm,27mm,32mm 3)Min. Order: 5 Tons Prestressing Hollow Expansion Anchor BoltPrestressed hollow anchor bolt is designed for hard rock at fractured zone,with high strength head,maily used for underground.Prestressed hollow anchor bolt consists of steel shell-expansion anchor head, hollow anchor rod, grouting stopper, arch plate and nut. ...