Extremely flexible – tremendously increased well being, one size fits a wide range of necks. Less strain to the neck. Great material stability – better against ageing and UV light. Better for allergies. Less friction (antifriction coat on the inside). Two sizes available : Small (Neck Size 22-30cms), Standard (Neck Size 28-37cms).Please note these can not be glued onto drysuits as the adhesive does not stick.