Abstract: A mouth blown sports whistle includes a mouthpiece that communicates with a sound chamber and emits an audio signal when pressurized air is blown into the mouthpiece and a second chamber that communicates via a passageway with the sound chamber. A visual member is housed in the second chamber in a retracted position so as to be capable of extending through an opening therein to an extended position when pressurized air enters the second chamber from said sound chamber to thereby render a visual signal of the blowing of the whistle. The whistle may further include a check valve associated with the second chamber to temporally hold the visual member in its extended position after the extension thereof and also a release valve associated with the second chamber to permit the visual member to return to its retracted position to ready the whistle for another combined audio and visual signalling.

Abstract: A chord-playing attachment for guitars and the like has a supporting frame which can be fitted to the neck of the instrument, and one or more chord-selectors removably attached to the frame, for pre-selecting chords to be played by pressing on a button. Chord-selectors can be interchanged on the frame.

Abstract: A fish hook has a tubular hollow main body with a retractable hollow needle fitted in its hook end, and a cap at its shank end where the hook attaches to a line. An antiseptic or anesthetic liquid solution is loaded in the main body, through the opening that is closed by the cap. When a fish is hooked, pushing in the needle, the liquid solution is ejected into the fish, enabling the capture of large and small fish alive and unhurt for biological study and to populate aquaria, as well as the catching of game fish.