Andy wrote:To be honest, the Halcyon reg looks more like a MK20 than a MK25 to me, though I suspect that it entirely cosmetic and the innards are likely to be closer to a MK25:
Well the 1st MK25's looked just like the MK20's It wasnt till the MK25.2 that the fins got added to the ambient chamber.
My bet is internally they are exactly MK25's
Personally I have removed the plastic caps from my MK25's and the plastic inlet cap.
I would also guess that there is some pricing restrictions on the regs. I doubt SP would produce a reg that is a copy of their own top of the line and let it be sold cheaper.
Not that it worrys me. My 2nd stages are only 30-40 years old so still have a few decades left in them yet and my 1st's are only just run in so they should last 50 years at least as long as SP continue making service kits available.