neck

I assume user-replaceable wrist seal systems are very common. Is it the same with neck seals? Or is it more common to not bother with replaceable neck seals? I also got a recommendation to choose a silicone neck seal instead of a latex neck seal. What materials are preferred for neck seals? I...

Our scuba dive guide had me do a back roll entry in the water and I believe I injured my neck. I have had headaches for two years that won't go away. Been to numerous doctors, MRIs, Cat scans, headache pills, chiro, etc. can get any help. Any one else have anything like this happen? Any...