These needles are the correct length, and should not puncture the liners if properly made use of WARNING: Product or service can't be returned or exchanged if liner is broken or punctured on account of poor inflation or needle use A flexible liner created for different head shapes provides comfort https://adult-medium-speedflex22692.smblogsites.com/30804904/speedflex-adult-large-things-to-know-before-you-buy