The Husqvarna 420A featured a 4-speed automatic transmission that made it incredibly practical for the Swedish Army. In addition, you could throw on some skis to bike to give the bike usefulness in winter.
The two-stroke single pushed power through the 4-speed auto with 4 centrifugal clutches. When you decelerated, the powerplant went into freewheeling mode, and then when you got back on the throttle, the bike would decide the appropriate gear based on rear wheel speed. For more information on the Husky automatics, check out this profile from BikeEXIF.
Husky automatic with skis in the winter bonus video footage:
This specific Husqvarna 420A (VIN: WN04030) is a numbers matching bike that is 99% original. The engine has been apart and the crank seals and rings were replaced.
Find this Husqvarna 420A for sale in Miami, Florida with an opening bid of $4,500