1.Buzzer alarm switch:on/off 2.Display size: 96*27*20mm description: 1,Numeral and color LED display 2, Step-up buzzer alarm ... ,Left and right obstacle indication 4,Numeral display from 1.8m to 0.3m 5,Display unit with built-in buzzer 6 ... switch:on/off 7,2,3,4 sensors for option8,Display size: 96*27*20mm package: Unit Weight: 0.56Kg 20 pcs ...