Review of the Magma Flopper Stopper.
https://setsail.com/magma-flopper-stopper-test/
My Flopper Stoppers are identical to the yellow ones in the Dashew article (they worked well for him, but based on thr test, will replace old with the Magma plates). The yellow ones work well on my boat but unfortunately are no longer made. I've considered a similar design could be inexpensively made DIY with a heavy plastic diaphragm and industrial wire mesh or expanded metal similar to these products used for safety railings and security cages;
https://www.easternmetal.com/m/stand...wire-mesh.html
Peter