Single cylinder deadbolt operates with a key on the exterior and a thumbturn on the interior * Deadbolt features biggest bolt diameter for maximum kick-in resistance and hardened steel deadbolt core that spins to resist saw attacks * Knob is field reversible to allow it to be used on both right handed or left handed doors * Snap and Stay design on deadbolt cuts installation time in half * Larger deadbolt thumb turn is easier to grip