Abstract: A hole saw, including a rotatable drill bit, a plurality of rotatable saw jaws disposed around the drill bit to encase at least a portion of the drill bit therewithin when the rotatable saw jaws are in a closed position, a fixed locking collar portion disposed at base ends of the plurality of rotatable saw jaws, and a movable locking collar portion to move with respect to the fixed locking collar portion, such that the plurality of rotatable saw jaws pivot away from each other into an open position as the movable locking collar portion moves away from the fixed locking collar portion.

Abstract: A personalized safety device for a hand held weapon for preventing unauthorized use of a hand held weapon having a trigger. The personalized safety device for a hand held weapon includes a housing which is coupled to a weapon such that the housing is positioned in front of the handgrip and trigger of the weapon. A pair of elongate guard plates outwardly extend from a pair of elongate slots in the back of the housing. A motor is disposed in the housing for extending and the retracting the guard plates from the housing. A computer is provided for controlling the retraction and extension of the guard plates by the motor. A scanner is mounted to the handgrip of the weapon and is in communication with the computer. The scanner obtains an image of the fingerprints and handprint of the user grasping the handgrip. If the scanned image matches data stored in the computer corresponding to the fingerprints and handprint of an authorized user, the computer activates the motor to retract the guard plates.