Century wise - different media valve?

[julianf]

I just took a look on their website and there is a valve I had not seen before.

This is the one I was expecting -

But these this one too, which looks the same sort of idea, but a bit more complex -

It's about £30 more for the latter one. I'm unclear on the pros and cons?

 

[brightspark]

not much difference from each other and will do the same job have you a lathe and a bit of gear . make your own; ive made the patterns up and cast them in aluminium easyer to make than steel the 1st one will run sand beads and grit no probs