What brand is this tester for?

[chicagomike]

What brand is this tester for? The connection end is rather large in diameter.

 

[vacuumlad1650]

my guess is Royal

 

[kenkart]

Too big

For a Royal. I think a Universal upright. one like the Anser..You are REALLY finding some rare goodies. this could also be for a early Birtman built Kenmore upright.

 

[coffeecanman]

That looks like it might fit my Kenmore Bugeyes. The thing that doesn't make sense, though, is that they weren't sold door-to-door, which makes one wonder why there would be a dirt meter for them. So perhaps not....

 

[bearwise]

Reminds me of the filter pad holder that Kirby salesmen use to show how much dirt is being pulled from your carpet when they demonstrate the vacuum.