What's unique about this liquid sprayer, is the 'stop/start' design. Rexair's sprayer had a hole in the top, over which you placed your thumb. Let up, or slide back, your thumb and the liquid spray stopped. The Electrolux sprayer operated whenever the machine was "on", and had only fine mist/broad spray settings for wax or shampoo.
This sprayer looks to have the ability to accept inch and a quarter hose ends, which was standard size (for many machines) at the time.