An anchor connector creates a secure connection between the anchor and lanyard of a personal fall prevention system when installed on structurally sound components (such as a beam, wall, or roof). Floors and walls with concrete can be secured with concrete anchors. To serve as a tie-off point for fall arrest devices, steel and beam anchors are clamped, welded or bolted onto structural steel (such as I beam, H beams, or pipes). To keep workers safe near edges and on slopes, roof anchors are installed on wood, steel, concrete, or raised seam roofs. An aircraft's surface cannot be penetrated to install an anchor, so vacuum anchors are used. Jamb anchors for doors and windows don't require permanent connections, so they won't damage finished walls. Whenever structural components are exposed on all sides, strap and cable anchors have loops or rings around their ends. Where overhead anchor points are not possible, freestanding anchors are used near edges or in open rail yards.