These needles are the proper duration, and should not puncture the liners if appropriately made use of WARNING: Products can not be returned or exchanged if liner is weakened or punctured resulting from incorrect inflation or needle use A flexible liner suitable for several head designs gives ease and comfort https://speedflex-adult-large07542.like-blogs.com/30607773/not-known-factual-statements-about-adult-medium-speedflex