Abstract: A conduit system for the flow of a fluid medium therethrough wherein the system is made up of a plurality of elongated conduit segments connected by means of fittings, such as straight connectors, elbows, T's or the like. The conduit segments are composed of opaque material and the fittings are composed of transparent material.

Abstract: An inlet valve assembly for a central vacuum cleaner system is provided with a mounting bracket plate having a circular inlet aperture therethrough and at least one electrical service aperture, and an adaptor for snap engagement with the mounting bracket plate through said inlet aperture. The adaptor comprises a deformable open-ended cylindrical connector of outside diameter slightly greater than the diameter of the inlet aperture, a flange projecting laterally from one end of the connector and adapted to overlie at least a part of the mounting bracket plate including the electrical service aperture, and an outer peripheral groove about the cylindrical connector and adjacent said flange. The deformable cylindrical connector is adapted for insertion into the inlet aperture until the flange abuts the connector plate, whereupon the edge of the inlet aperture snaps into the groove in the outer surface of the cylindrical connector to securely attach the adaptor to the mounting bracket plate.