They are typically called backup lights because they are used as a secondary source of light to help the driver see what is behind the truck
Dayton Parts Batco: 321122
International-Navistar: 1676715C1
Mack: 20QE1129
Inner Diameter A: 4"
Fortpro 4-Pole Relay Switch Replacement for 2MR358A, 85129178 | F235427 3803471 They are typically called backupSpecifications: Part Type: Relay Switch Terminals: 4 Voltage: 12 V Color Finish: Black CrossReference: Mack Volvo: 85129178, 1825898C94, 1826634C94, 1807230C2, 1653460C1, 1693494C91, 2MR358, 2MR358A, 20563872 Navistar International: 1825898C94, 1825898C91, 1826634C94, 2587934C91, 1807230C1, 1826634C92, 1826634C91, 1826634, 1653460C1, 1693494C91, 1825931C1, 1831646C1, 1825908C1