Description Reviews Q&A Our bulk roll Reinforced Mylar material has a foil faced backing and a 1" thick, fiber-based insulation layer. It has been specifically designed for high heat environments and can be used in under-hood applications. This material is 54" wide and sold by the running foot. NOTE: Quantity refers to # of feet off the roll. For example: qty 1 = 1' x 54", qty 2 = 2' x 54", qty 3 = 3' x 54", etc. Please contact us before purchasing to determine if this product qualifies for your use-case. Due to shipping size regulations, we are limited to the following roll sizes by foam thickness: up to 45 feet of 1/4", up to 30 feet of 1/2" and up to 18 feet per roll for 1".