Abstract: A screw-type fastener having a threaded shank and a head integral therewith, and adapted to be driven into a structure by axial rotation about its longitudinal central axis in a driving direction such that the head is countersunk, is improved by forming the head with at least two ribs protruding from the surface thereof and extending radially outward from the central axis. The ribs define a corresponding number of sector-shaped cavities adapted to receive a filler material for engaging the ribs so as to prevent the fastener from axially rotating in a direction opposite the driving direction and to thereby secure the fastener against loosening.

Abstract: The invention is concerned with a bathtub having a bottom wall, a pair of sidewalls and opposed first and second end walls integrally formed with the bottom wall, the second end wall being angularly inclined outwardly to define an abutment surface against which a person lying in the tub may rest, and water inlet means for filling the tub with a mixture of hot and cold water. According to the invention, the water inlet means extends through one of the sidewalls and is adapted to discharge a flow of hot and cold water along the one sidewall in a direction towards the second end wall so as to impart to the water a circulatory movement as it fills the tub and to thereby uniformly mix the hot and cold water and provide a uniform water mixture having a substantially constant temperature.