Robertson Worldwide warrants to the purchaser that this ballast will be free from defects in material or workmanship for a period of 2 years from date of manufacture when properly installed and under normal conditions of use.
http://www.amazon.com/Robertson-Worldwide-BLU0070A04900-pressure-ballast/dp/B005H7PYIY/ref=sr_1_77?ie=UTF8&qid=1375897321&sr=8-77&keywords=robertson+ballast ; http://www.robertsonww.com/products/spec_sheets/BLU0070A04900.PDF