Lightweight adjustable anchor designed to clamp directly to the flanges of various size ‘I’ and ‘W’ style beams. A swivelling D-ring allows for a compatible attachment point of a personal fall arrest system (PFAS) for a single user. The sliding jaw can be adjusted to the needed width and placed over the beam and then secured in place with the locking detent pin. With the screw adjustment feature, the clamp can than be securely attached to vertical or inclined beams to prevent movement.