The 1089951330 contact block is sits on the backside of the emergency stop button. This sends a signal to shut down the compressor when the emergency stop button is pushed. This contact block was used on a wide variety of Chicago Pneumatic and Atlas Copco air compressors.
The part number may be displayed in your manual as 1089951330, 1089-9513-30 or 1089 9513 30.
2204135111
1630144405
1089949693
1089951334
1089948298