Ngokuvumelana nezidingo ezintsha zokusabalalisa ukukhanya okujwayelekile kuzwelonke, izibonisi zingakhetha ukuthi zifane noma zingahlangabezi izidingo ezengeziwe;I-decibel ceramic buzzer ephezulu kanye ne-chip yomshayeli ezinikele isetshenziselwa ukukhipha ikhwalithi yomsindo ozinzile futhi ejabulisa;Insimbi engagqwali noma ubakaki ofuthwe ngepulasitiki ngeke ugle iminyaka emi-3.