Abstract: An aeration element for gasification or aeration of liquids includes an essentially flattened, rigid support element having a substantially oval cross-section and corrugated outer surfaces, the corrugated outer surfaces including ridges defining grooves therebetween; a threaded opening for receiving a cooperating fitting for connection to an air supply; and a flexible membrane of elastomeric material disposed around the support element, The membrane has a plurality of slits, and wherein compressed gas is introduced between the support element and the membrane, the gas can escape via these slits into the surrounding liquid. A retaining clamp holds the membrane around at least one end of the support element.

Abstract: A pet toy having a first part with internal threads, and a second part having external threads. When the first and second parts are threaded together by interengagement of their internal and external threads, they cooperate frictionally with one another to prevent, or at least to make difficult, an unintentional unthreading of the two parts from one another, wherein the threaded-together parts form a pet toy. To make unintentional unthreading even more difficult, additional engagement means can be provided on the first part and additional cooperating second engagement means can be provided on the second part.