Hey Guys
Great machines. What model was the yellow Trident?
The Electrolux book I have lists a model U136 (trident) in 1965 - covering Blue-grey horizontal ribbed plastic with handle and end covers in light grey plastic
It also lists models U137 (Challenge) (same as model 64) and U138 (Challenge) (same as model 65)in 1965 both in light grey horizontal ribbed plastic with maroon ends and handle
The Challenge and Trident models must have at least lasted over several years in this case
Doug