A zipper segment for transverse direction application to a bag film web in which the profiles are of unequal lengths and joined together at their ends. As a result, the shorter profile is placed in tension. During bag formation the longer profile is initially attached to the bag film web and the shorter side is attached only by the engagement of the profile interlocking members and end seals. The shorter side, which is not directly attached to the web, nonetheless remains close to the web as a result of the tension imparted on the short side by the longer side.