I’ve used one in the past. They work ok, I guess. But I prefer to prevent the "water-in-the-ear" situation all together. I use Doc’s Ear Plugs. Been using them for a few years now. Doc’s makes both the vented and the non-vented kind. IMPORTANT..... You MUST use the VENTED ear plugs for scuba diving.
NEVER use the non-vented ones for diving.
Your Local Dive Shop may sell these and they are able to fit you properly for them.
Safe Dives
Ron sends