end when the device is submerged or partially submerged the device is designed to fill automatically with water while a bathtub is being filled application_number US 31326902 A description fig1 is an illustration of a first embodiment of the cushion device without a cover of the pillowcase type this will be referred to as the u201c core u201d of the device the core consists of a flexible hollow shell 1 spacing means 2 within the shell and a plurality of protruding tubular fluid control ports 3 these ports include an upper inlet outlet fitting 3 a near the upper end of the core and a lower inlet outlet fitting 3 b near the lower end of the core each fitting having a closure means 3 c also as seen in fig3 the core incorporates weight means 4 in its base the flexible hollow shell 1 is made of a flexible and water proof material and is mounted with the port fittings 3 a and 3 b and is watertight when the ports are closed by the closure means 3 c the ports allow water to enter the core and once closed in to provide desired body supporting function and the contained water keeps the cushion at the bottom of a bathtub and at positions desired by users instead of floating on the water surface or escaping from the desired position when the user moves and releases pressure on top of the cushion the spacing means 2 is made of a flexible elastic and durable polymer material for example in the form of.