TubeNet

From the same seller as 691 size Amati:
http://pages.ebay.com/link/?nav=item.vi ... 1564701553

Same bore as current one (20.2mm) the bell is 45cm (5 cm smaller) and different tuning slide design.
http://www.cerveny.biz/helikone/

Seller sold more recent version:
http://pages.ebay.com/link/?nav=item.vi ... 1505422588

hrender wrote:That's a beautiful instrument, especially for a 1948 vintage horn. I have no idea how hard it would be to get it to the US in the same condition.

Seller specializes in brass instruments and has a good feedback, I would ask questions if he shipped to US and what was the outcome.