Amplifiers; Headsets; Photodiodes; Semiconductors; Transformers; Wattmeters; Wavemeters; Electric circuit switches; Flashlights for use in photography; Frequency meters; Laser pointers; Laser rangefinders; Optical lenses; Optical sensors; Power controllers; Protective eyeglasses; Protective spectacles; Safety goggles; Signal generators; Telecommunications equipment, namely, fiber-optic transceivers, fiber optic repeaters, converters and optimizers, wave division multiplexers, free-space optic...