Abstract: An improved self-sealing valve for use in a fluid fillable article includes a main body portion and a channel portion for receiving a fill tube. The channel portion within the main body portion is a substantially flat, elongated conduit having a pair of opposing sealed edges and, between said edges, a pair of flat flexible wall members facing each other to form a fluid seal when they bear against one another. The conduit is open at both ends. The channel passing through the valve has constrictions along its wall which change the contour of the channel so that a fill tube passed through the channel does not dislodge a sealing gel from within the channel. When fully inserted, a fill tube seats firmly against the constrictions and prevents back leakage during the filling process. Upon removal of the fill tube, the constrictions wipe the sealing gel from the fill tube shaft and retains it within the valve channel.