A vena cava blood clot filter is described that is attached to the walls of the vena cava by barbed anchors. A multiplicity of menu options are automatically and sequentially displayed, one at a time, in a display window of a computing device. The semiconductor structure also includes a III-nitride epitaxial layer of the first conductivity type coupled to the first surface of the III-nitride substrate, and a first metallic structure electrically coupled to the second surface of the III-nitride substrate. When the animal is to be lifted and carried about, the aft harness may be affixed to the front harness section to support the ladder part of the animal. The flexible opaque diaphragm is located between the LED and the phototransistor.