I operate an Authorized Rainbow Service Center, and have for many years. Let me clarify the Power Nozzle info. When the D3A was introduced in June, 1980, Rexair did not yet make their own Power Nozzle, and continued to use the Power Nozzle they bought from Eureka. This Power Nozzle was designated R1024G. In February, 1981, they brought out their first Power Nozzle they built themselves, the R1650A, with a 3 wire grounded cord, as UL required. In the fall of 1981, the Power Nozzle was double insulated, eliminating the need for the third wire, and it became Model R1650, with a 2 wire cord. Simultaneously the Rainbow machine became the D3C (in the United States, there were MANY other variations for international markets, for example D3B was Canadian.) The D3C was grounded and used a 3 wire cord to the wall, but had (as its only change from the D3A) a 2 wire receptacle for the Power Nozzle. The R1650 Power Nozzle was succeeded by the R1650C (again in the US only) which introduced the new style pivot arm and the slide valve. During R1650C production, the two piece cord, which could be disconnected up near the hose handle, was changed to a continuous length of cord from the Power Nozzle to the Rainbow. This was an aggravation to users, but was mandated by UL which required this type of cord on any vacuum cleaner rated for wet pick-up (Of course the Power Nozzle wasn't used for wet pick-up, but UL somehow felt this arrangement encouraged safe operation using the non-electric hose.) The arrangement continued through the nearly identical R2800C (US) Power Nozzle used with the D4 machine. When the SE machine came out in 1990, it was equipped with a UL approved electrified hose, an arrangement which has continued through several variations and is used with the new e2.