or gaseous from within the volume that is defined by the inside of the plenum 15 and the volume 58 inside the drain and above surface 55 of the trapped water 54 thus as incoming compressed air which is indicated by arrow 57 fills the volume 58 the hydraulic pressure or pneumatic pressure of the air is transmitted by those processes that are well known to those who are skilled in the hydraulic arts such that a net force f u2032 is conveyed to the blockage obstruction 56 the final result is that the blocking obstruction 56 is pushed downward along the walls 53 of the outflow drain 52 to a wider portion thereof thereby ultimately affecting the desired result which is removal of the blockage 56 from the water drain 52 of the basin 50 although the invention has been shown and described with respect to a certain preferred embodiment or embodiments certain equivalent alterations and modifications will occur to others skilled in the art upon the reading and understanding of this specification and the annexed drawings in particular regard to the various functions performed by the above described components assemblies devices etc the terms including a reference to a u201c means u201d used to describe such components are intended to correspond unless otherwise indicated to any component which performs the specified function of the described component i e that is functionally equivalent even though not structurally.