A reverse-acting pressure relief device (10) is provided comprising buckling-control structures, namely pocket regions (20, 22) and belt regions (24) having differing material thicknesses. The pocket regions (20, 22) generally comprise areas of reduced material thicknesses and serve to weaken the structural integrity of the bulged section (12) of device (10) so that reversal can be initiated at lower pressures. Belt regions (24) generally comprise areas of enhanced mechanical properties that assist with reversal control and opening of bulged section (12) thereby ensuring complete opening of the device (10).