Abstract: Protective devices, such as, for example, helmets, have one or more efficient, fluid-containing shock absorbers in place of protective devices' original shock absorbing material to minimize the overall weight of the protective devices. The more efficient, fluid-containing shock absorbers yield improved impact force attenuation but occupy substantially less volume and, consequently, less weight, than the original shock absorbing material.

Abstract: The water-filled stairs involves a modular staircase that is to be used on a temporary basis, and which is of hollowed construction so as to be filled with water when in use for the purpose of weighing down the staircase. The water-filled stairs is further defined with a plurality of steps adorning a top surface, and a flattened bottom surface. Distal ends of the water-filled stairs include a hook or connecting bar such that consecutive staircases may be attached to accommodate the needs of a particular application. Each staircase includes a male threaded port adjacent a top distal end as well as a bottom distal end. A flexible hose attaches in between the male threaded ports of adjacent staircases in order for a single water source to fill all staircases simultaneously.