Features: Part number: 156T1978A. These time switches trippers suitable for T100 Series. Suitable for 1101-7, 1101B, 1101B-P, 1101B-PC, 1103B, 1103B-O, 1104B, 1109A, 1109A-O, 1109A-P, 1109A-PC； 7000 series: 7209A, 7300, 7302; 1800 series; Please confirm the model before purchasing. They have dustproof, waterproof and other characteristics, high protections levels, can adapt to different use of the environment. The structure is make of metal, strong, can stand the test of time, with high stability and reliability. Easy to install: Loosen fixing screw on the trip unit, slide the trip unit to the timer dials for on/off action at the required time, and tighten fixing screw. Specifications: Component: metal Size: about 2.6x1.1x1cm/1.02x0.43x0.394inch Package Includes: 6pair Time switches Replacement Trippers note: Please allow 1-2cm errors due to manual measurement, make sure that you do not mind before you order. Due to the difference between different monitors, the picture may not reflect the actual color of the item.