Anchorage connectors install on structurally sound components (such as a beam, wall, or roof) to create a secure tie-off point between the anchor and the lanyard on a personal fall prevention system. Concrete anchors install on concrete floors and walls. Steel and beam anchors are clamped, welded or bolted to structural steel (such as an I-beam, H-beam, or pipe) to serve as a tie-off point for a fall arrest device. Roof anchors install on wood, steel, concrete, or raised seam roofs to keep workers safe near edges and on slopes. Vacuum anchors are used when surfaces cannot be penetrated to install a anchor, such as when working on aircraft. Door and window jamb anchors don't require permanent connections that can damage finished walls and door frames. Strap and cable anchors have a loop or ring around each end to wrap around structural components when the component is exposed on all sides. Freestanding anchors are placed near edges or in open rail yards where overhead anchor points are not possible.