Norpro developed sound attenuated enclosures (sound shields) for its line of marine generators. With the help of advanced polyether foam, Norpro was able to create the quietest line of generators on the market. 2002 also marked the year Norpro introduced their alternative fuel series of generators, offering several different GM based units for those who do not want a diesel generator, or just prefer Liquefied Petroleum Gas (LPG) or Natural Gas (NG).