A pair of mating sealing jaws for forming a seal between opposing heatsealable surfaces includes a first jaw and a complementary second jaw. Each jaw has a sealing surface that includes at least two peaks separated by a valley. Each peak includes a first face and a second face. A phantom line bisecting the valley defines a first angle between the phantom line and the first face and defines a second angle between the phantom line and the second face such that the first angle differs from the second angle.