I would buy any good aftermarket 350 balancer.That does not have the interia ring visable.I walked though the pits a couple of months ago at Sears Craftman Nationals looking at all different class's of cars.And I did not see any balancers that had the fluid in them.What does this mean?Does the fluids viscosity change with the temp?and how does this affect the balance?What happens if the fluid starts to leak out?Would it then affect the balance because the cavity is no longer filled completely?Does the fluid wear out after time spinning at what ever r.p.m.s. after so many years?Maybe I am overthinking this L.O.L.