A sealing device is provided for use with a fitting. The fitting has circular port and a flow path with a longitudinal axis. A circular port encircles a portion of the flow path opposite the port with the sealing device inserted into the port. The sealing device has a circular top with two opposing surfaces depending therefrom but inclined so the surfaces are closer at the top. A continuous sidewall joins the periphery of the two surfaces. The opposing surfaces are inclined and spaced apart further at the top than at an end opposite the top. A cylindrical hole through the opposing surfaces encircles the flow path during use.