Retekess TD158 Pager System, Mini Call System Pager, Outdoor 500M, LED Ear Display, 4 Call Modes(1 Keyboard Transmitter + 20 Pagers)LED tube display pager; makes the restaurant pager correctly accessible; suitable for clinics; Food courts and so on Low battery reminder; The digital tube displays lo if the pager power is too low; Prevents power outages and disruptions in operation set reminder duration; easy to change mode time from 1s to 250s; the number 0 means continuous warning; The default value is 30 seconds; You can set the correct reminder time if necessary; widely used on