... .Use for water,air,oil etc 3.Competitive price Quick Connecting Tube Fitting--epu/Apu Union Angle/Straight Description: 1) Suitable ... take tubes off.3) Once inserted to the nut,the tube would not easily loose4) Nickel-plated metal body ensures anti ... pre-coated sealant6) Quick and simple tube insertion7) Compact,lightweight design8) Advanced, well-proven tube retaining system9) Re-usable thread seal