These needles are the correct size, and will not puncture the liners if thoroughly used WARNING: Item cannot be returned or exchanged if liner is damaged or punctured due to improper inflation or needle use A flexible liner suitable for different head styles gives convenience and stability Detachable humidity-resistant liner https://devinoztza.yomoblog.com/37101719/indicators-on-adult-medium-speedflex-you-should-know