US Patent 7794176 Height adjustable water control conduct

An adjustable height drain has an elongate base element and an elongate drain element. The elongate base element has walls extending upwardly from the elongate base element. The elongate drain element has a top surface supported by downwardly extending walls, and the top surface has a plurality of apertures enabling water to drain through the top surface. First interlocking elements are vertically spaced from each other on the upwardly extending walls, and second interlocking elements are spaced apart from each other on the downwardly extending walls, enabling the elongate drain element to engage the elongate base element in either a first position or a second position, adapting to change in surface elevation.