Socket screw plugs screw into and seal threaded openings in pipes, fittings, and other parts that carry pressurized gas or fluid. Some plugs feature a cylindrical design for a flush or recessed fit in the mounting component while others feature an integrated flange. This flange prevents them from being overtightened and provides a place for an O-ring to help create a better seal. They feature a hexagonal or Allen key drive for high torque and to resist cam-out when tightening or loosening.