3501-26 Single Cylinder tanks for 1926-29 models. Probably Germany-sold, NOT Replicant Metals for sure. Have a few discrepancies when laid side to side, note locations of under tank frame clips, not across from one another. Can be used together with no modifications, just need some ingenuity. Insides show light rust film from sitting last 10 years since I have had them. All openings have good threads and solder joints look secure. Will need back bone mount holes drilled for your frame.