That makes sense, early on we had 3 needle wheels, US 9410, European 9410, European 9420. We initially used the European 9410 in the US 9420, since a US pump does 36000rpm due to the 60Hz and a Euro one does 3000rpm at 50Hz, we felt it would be comparable, it wasn't quite and this resulted in underperforming 9420's and 9460's. We then used the Euro 9420 needlewheel for a very brief time which resulted in a big overperformance, this was temporary until a US 9420 needlewheel could be made which is what you have. I didn't know any of these Euro 9420 needlewheels were still out there, we made about ten pumps like this over just a couple weeks. Can you PM me the address? Sorry I didn't think of this.