I installed a 4 way last fall which was purchased new at the time and it was shaft driven.

Shaft driven magnetically coupled , yes since 2004.

yeah, that looks right, sorry my bad. The smaller version doesn't disassemble the same way so you don't see the shaft attachment, I was assuming that was what was meant by shaft driven. So does the smaller version use weaker magnets?

Proportionally yes, they use different strength magnets and flux collectors, not to be confused with flux capacitors:)

So when you say smaller version do you mean the 1000 gph or less Squirt is the smaller one? And the up to 2500 gph Super Squirt is the larger one? And the 1000 gph one doesn't work as well?

I've never used the "super squirt" but the smaller version I was referring to was the "OM squirt". It worked well and is a good product but I personally found it to require too much maintenance to keep it working, especially when it's connected to a closed loop under a tank when space is limited.

The larger version I was referring to is the "OM 4 way". It's a little more money but a stronger unit that requires a fraction of the maintenance. So for me well worth the extra money, even if used at a lower flow rate.

Ah ok. Thanks!