Sizes in metric (mm):
MPW092 Parker 2-042 ID 82.27 W1.78
MPW115 Parker 2-047 ID 114.02 W1.78
MPW142 Parker 2-161 ID 139.37 W2.62
The MPW motors themselves have a motor shaft seal already. This O-Ring is to seal the front face of the motor. This is not included with the motor and users can source these from common seal/industrial suppliers.
For full range of material/temperature options for your application: www.parkerorings.com