WARNING - Do not use pipe thread sealant or Teflon® tape on any flare ends because you will not obtain a leak-free seal. Keep flare end of fitting and flare seat of connector nut free of grease, oil, pipe thread sealant and Teflon® tape. Use a wrench only on the hex surfaces of the fittings. Never loosen a connection after tightening-this may cause a leak. It is always better to tighten more if a leak is detected. If fittings is installed improperly, remove fitting, reapply pipe thread sealant or Teflon® tape and reinstall properly per instructions. Do not use a pipe wrench or channel lock pliers on the connector flare nut. The nut can be damaged or you will not achieve sufficient tightening torque which will cause a leak. Use open-end or adjustable wrenches only. More help at www.fixitnow.com