Provided is a novel mono-axial taper lock screw for connecting a connecting rod to bone. The screw is capable of being secured to the underlying bone while the screw head adapted to securely hold a connecting rod is rotated about the longitudinal axis of the screw to facilitate a stable connection to the connecting rod. The screw head can be partially locked to hold the device in place while permitting manipulation of the spine. The screw head can then be fully locked securing the connecting rod into a selected position. The screw is configured for easy insertion and connection as well as easy removal and disconnection from the connecting rod. Also provided is a bone fragments. A method of fixing bones or bone fragments is also provided.