Out of all the commercial static flopper stopper systems available here in Aus they are the most popular.
Easy to assemble and very effective in opperation.
I have a few friends that have them and all are happy.
My neighbour wuth a Nordy 50 (active fin stabilisers) has them for use at anchor.
I made my own , initially using drouge type bags but then to rubber flapper type , (similar to Ocean Torque) one of the good thinks about this system is that they are quiet in opperation.
Others us s/s flaps that can generate a bit of active noise.
One other thing is to use dyneama rope as opposed to chains or wire to reduce the noise factor.
Boat Stabilizers - Ocean Torque Boat Stabilizers Stop The Roll