Surface bolts Exceptional strength and durability provided by interlocking construction of heavy gauge track and rod Designed for superior strength and smooth operation Concealed screw design enhances appearance and security Tension spring holds the bolt in the desired position and a permanent stop prevents rod disengagement Track assures smooth operation and interlocks with side edges of rod to eliminate marring Decorative 5/8-in diameter knob designed to facilitate bolt operation Comes standard with universal, mortise, and surface strikes Constructed of solid brass 15/16-in throw, unless otherwise specified