BLACKHAWK! describes this item as follows:
This enhanced version has internal dividers to separate the mags and has an elastic retention system to prevent the mags from "slapping" or ejecting from the pouch. Non-slip leg straps. HOLDS 4 MAGS!Blackhawk® IVS - Intercooler Venting System
IVS stands for "Intercooler Venting System". This technology helps improve the structure of packs and rigs through stiffening of the back panel and provides enhanced stability during movement as a result. In addition, the molded channels on the platform increase air flow between the equipment and your body to provide additional comfort during those extended missions.
The molded back panel is constructed of a "tri-laminate" of nylon, closed cell foam, and durable moisture wicking material, all heat compressed into one solid platform, as you can see on the product shown on the left.
Compare this technology to our competitor's products and you will immediately know why Blackhawk is the operator's first choice.
Blackhawk offers over 100 products that incorporate IVS technology for increased comfort and performance.