Gelang s23yu is waterproof and fall-proof, while s15 is not waterproof and fall-proof. GELANG)S23 loudspeaker, outdoor promotional selling tapes, wireless microphone, audio speaker, small bee's square dance subwoofer for teachers.
Audio refers to a set of audio systems in which electrical equipment is combined to produce sound. The development history of audio technology can be divided into four stages: electron tube, transistor, integrated circuit and field effect tube.