Abstract: An adjustable manhole is disclosed having telescoping tubular members which can be fixed in a number of relative axial positions. One member carries a series of transversely oriented ribs and grooves in the interface between the members, and the other member carries a smooth wall in the interface. Locking means are engageable in selected grooves to fix the relative positions of the members.

Abstract: A water trap for use in sinks and other drains, wherein two members which together form a water seal are adjustably and releasably secured together by a threaded connection. Means may be provided for handling water from two separate sources, wherein the trap performs two separate trap functions but ensures that a water seal will always be maintained even though only one source may be draining into the trap.