Sentry lockdown screws, (LDS) utilize an external thread (ET) design that moves the threads outside the pressurized or wetted surface of the wellhead equipment. They utilize a robust Unified National Coarse (UNC) thread for the lockdown screw itself and the packing gland nut to minimize any galling. Additionally a one piece HBNR compression packing element with molded metal end caps to provide a dependable seal in multiple pressure ranges and service environments.