HH2® ENERGY INC & DR. DEREK ZUPANCIC INVENTOR of the HH2® Hydrogen cells reports the HH2® system appears to be the only one worldwide that works with compressed natural gas and LPG or Propane systems to clean up exhaust emissions, boost engine performance and nearly double fuel economy. Tests for over 3 years on a Honda CNG civic show in daily driving (200+ miles) by owner, now a supercar WOW.