0661100039 is an OEM o-ring from Chicago Pneumatic and Atlas Copco. This o-ring was used on a wide array of their rotary screw air compressors.
Please contact us with your model and serial number for confirmation this item works with your air compressor.
Part #: 6231638800
Part #: 2200902714
Part #: 2200902301
Part #: 2200902354
Part #: 2200902017