Abstract: An outlet assembly is provided for securement into a receiving profile defined upon the bottom surface of a sink for laboratory or like usage. A sleeve is contoured such that an upper lip provides a sloping surface toward the interior of the sleeve with the lip being contoured slopingly toward the interior of the sleeve for further gravitational urging of liquid into the interior of the sleeve. The lower surface of the lip is contoured to receive a lock-nut which includes a grooveway configuration to enhance the securement of a locking-nut relative to the sink or a gasket disposed between the lock-nut and the lower face of the sink. The sleeve may include a contoured receiving profile for a filtering disk which is selectively placeable within the sleeve and which includes a series of fluid flow passageways.