Sports whistles; Glow whistles; Dog whistles; Signalling whistles; Training aids for animals (signalling whistles and clickers); Whistle alarms; Whistles (warning apparatus); Whistles for signalling; Air break switches; Audio switching apparatus; Branch switches; Data switches; Electric switches; Electrical switches; Light switches; Computer based control apparatus for machine tools; Lasers for machine tools; Lasers for controlling machine tools; Microprocessor-based control systems for use with machine tools; Pressure measurement tools; Sensors for use with machine tools; Alarm bells; Alarm bells, electric; Alarm control apparatus