Here is a picture from my 1935 Vitalic catalog showing different types of hoses. Also in the photo are a CD 1049 with rubber hose insert and one out of the insulator. I think that Continental made these as well and the R-B 1 was to be an improved design. These hose inserts are not marked but if you enlarge the picture you can see Continental Garden Hose and Erie Cord Garden Hose both have the ribbed outer surface like the inserts in the CD 1049's. It would have been nothing for them to make a hose and cut thousands to length for the insulators. Would have been nice to have them marked. I'm keeping my eyes out for the insert Rick has but it is probably hard to find or could have been a prototype.