Just a little more information, too ... it's not the neck, it's the head.
An interesting note - when we began the process of the ZipSeal neck ring, we researched the size and found that 99% of people would fit in the size we chose. Little did we know that, on the whole, divers have bigger heads than the average public.
Our current ZipSeal neck ring can fit 95% of divers - it's the 5% that don't have the option but still DO have the option of getting the regular neck seal.
There are a number of divers who are right on the edge - for those, the important thing to remember is:
1: Do not put your hands inside the RING when taking off the neck seal - just put your fingers inside the seal (your fingers inside the ring makes the ring smaller) and,
2. Pull the ring straight up - do not let it move to an angle, i.e. pull up higher in the front and it goes lower in the back. The reason for this is it makes your head dimension bigger.
Shape of head can affect the fit, too.
We can fit 95% of you the way it is. For the rest, you option is only the regular neck seal.
Yet we do want to make what we have better. It just may be a while.
Thank you for asking!
Susan Long