This Astro Flight 4005A Rapid Charger is a very early device, made around 1978 for charging 4, 6 or 8 cell batteries. As other early chargers the 4005A is timer controlled , also there is a switch for selecting charge current. For slow charging there is a trickle charge option with an additional red control lamp.
The Astro Flight chargers had been used of course for early electric flight airplanes, but also for charging the batteries of rc-cars. Delta sold Astro chargers before they started making their own chargers.
Astro Flight is known for their Astro Cobalt motors until today, but infact this company was founded back in the late 60´s making motors powered by Ferrite magnets. This company still exists today, making Cobalt motors, brushless motors, speedcontrols and chargers for radio control use and motors for industrial purpose.