These needles are the proper duration, and will not puncture the liners if effectively employed WARNING: Merchandise cannot be returned or exchanged if liner is damaged or punctured resulting from incorrect inflation or needle use A versatile liner made for various head shapes gives comfort and balance Removable humidity-resistant liner https://adultmediumspeedflex17248.suomiblog.com/a-secret-weapon-for-adult-medium-speedflex-46645258