The disclosed screw assemblies include a screw that attaches onto the bone, a housing member that connects and inter-locks the bone screw to the rod, and one or more looking members that permit immobilization of various components of the assembly relative to one another while still permitting some relative movement. The motor applies force to the strike plate in accordance with a predetermined curve to bring the product to a soft stop. The activating member includes two tail fins and a positioning member respectively extending from the second surface. A corresponding electronic device is also disclosed. Output from the significance function generator is coded using the modified Z-coder.