Variable Function Insert (VFI) - rubber based insert that fits securely around a multi-piece, "flat base" rim. The device is inserted into a tubeless tire, which is in turn fitted around the wheel.  The three components complement each other as they are all designed to work together to provide optimum mobility. Two types of wheels are necessary for use in this "assembly" …either a "2 piece bolt together" or a "3 piece lock ring style" which utilizes a lock ring and side ring to secure all the parts together.

In addition, the VFI provides improved survivability for vehicle occupants due to the nature of its engineered design and the added benefit of the dense rubber based material from which the product is manufactured.

The Hutchinson VFI is designed for dual use: a beadlock and runflat, thus providing maximum performance in all terrain conditions. Most importantly, the VFI meets all U.S. military standards, as well as the FINABEL and NATO standards…making the VFI the most widely used runflat in the world.