The Newage Series 4 350-28700 has now been discontinued but we can offer our Compatible Regulator as a replacement. The EA440 is accepted worldwide as the only Quality, Legal and Cost effective alternative to using the Series 4 350-28700. It's also Compatible with the following Stamford models:
SX440 - 350-24500 - E000-24010 - E000-24015 - Onan 305-0824.
Brochure & Manual: http://www.sp-powerworld.com/products/newage-series-avr/ea440