Calculating scales; Calculators and calculating machines; Microscope objectives; Speaker microphones; Telescopic sights; Audio speaker enclosures; Bass speakers; Conical attachment to an audio speaker for diffusing and distributing sound as it is transmitted from the speaker; Cover glass for microscope slides; Electronic calculators; Electronic signaling mechanism, namely, a train control system used in the railway industry for detecting and controlling trains, ground faults, broken rails, po...