An inflatable, conformable, cushioning, packaging product comprises a plurality of individual inflatable strips of multiple bubble cushioning structures. Each individual inflatable strip has a plurality of bubble chambers with each bubble chamber interconnected to an adjacent bubble chamber by an interconnecting passageway which is smaller in size and internal volume than the bubble chambers, but which is sufficiently large to enable air volume and pressure in one inflated bubble chamber to be transmitted to adjacent bubble chambers for distributing a shock load on one bubble chamber along the entire length of the individual inflatable strip of interconnected bubble chambers. Each individual inflatable strip is defined between two laterally extending spaced apart peripheral seal line which have an undulating configuration free of corner shapes which could concentration stresses.