New MPE film provides taste free qualities of polyethylene with the added benefit of extra strength over typical PE films. The M in MPE stands for metallocene, a special catalyst used in the manufacture of the PE resin. It forms a PE that is more consistent and even in structure, resulting in greater strength and resiliency, making it ideal for reservoirs. This added durability allows it to handle hot water. It is BPA PVC free, of course. New HydroStatic backer plate creates a wider and lower profile. A traditional reservoir barrels out and forms a straight tube when filled, interfering with a packs ability to fit the body. The HydroStatic plate shapes the reservoir to ensure pack fit is preserved for optimal stability and comfort.