tanks Edgar!
I don't know if these one had a switch, I wish they have. I also thought about getting an electric hose of an old National, but they're very very rare if not impossible to find, I have some hoses from my Nationals that would fit but they don't have the switch. For now, all that I could do is ask my doubts to the seller and cross my fingers.
Oh, I forgot! I sent you a message in youtube, check it out =)