What about one of these? (I don't have one for sale, before you ask)
Vandagraph Home of the VN202
Damned fine peice of kit, if you ask me! Plus you get everything you need to get started including *two* flow restrictors - one for a direct DIN connector and another for an inline low pressure inflator hose connector.
[EDIT] - Didn't realise that the Pro HE you mentioned is effectively just a stripped down Teledyne, from what I can see. In that case - and providing you already have an oxygen analyzer - it might be a better option as the addition of an oxygen cell/dual displays to the Teledyne adds quite a bit of money to the unit!
