A fitting for use with metal, corrugated tubing having peaks and valleys includes a nut configured to receive the tubing; a sealing member for placement in a valley of the tubing, the sealing member including a sealing surface; an adaptor configured to engage the nut, the adaptor including an adaptor sealing surface; and an anti-tamper sleeve configured to encompass the nut and adaptor; wherein upon assembly, the tubing is compressed between the adaptor sealing surface and the sealing surface.