A locking sheath and knife combination is provided that includes a spring biased member that partially extends out of the handle of the knife and interacts with a catch on the sheath for securing the knife to the sheath. When the user wants to extract the knife from the sheath, the spring biased member is squeezed as the handle is grabbed, which rotates the spring biased member to be substantially fully contained within the handle of the knife, and is secured there by the lock spring plate. When the knife is inserted back into the sheath, a protrusion on the sheath interacts with the lock spring plate to automatically allow the spring biased member to rotate out of the handle, thereby securing the knife to the sheath.

A utility knife includes a housing and a blade carrier movably mounted to the housing. The blade carrier includes a blade supporting surface for supporting a blade, wherein the blade carrier is movable between a retracted position with at least a substantial portion of the blade retracted in the housing, and a first extended position with at least a portion of the blade extending outwardly of the housing. An actuator is operably connected to the blade carrier and is operable to move the blade carrier between the retracted and extended positions to, in turn, move a blade located on the blade carrier between the retracted and extended positions. A biasing member biases the blade carrier toward the retracted position. A stop member is movable between a first position and a second position. In the first position, the stop member is engagable with the blade carrier to thereby limit extension of the blade carrier and blade located thereon to a second extended position spaced inwardly on the housing relative to the first extended position. In the second position of the stop member, the stop member is spaced away from the blade carrier to thereby permit movement of the blade carrier and blade located thereon to the first extended position.