Taylor Made's Premium Fender Covers are knit from heavy weight, high tenacity solution dyed polyester yarn that stands up to sunlight, abrasion and harsh environments. The fabric is a circular knit construction to eliminate lateral seams (that can fail due to the added friction ) and has a high degree of elasticity to maintain its shape and ensure a nice tight fit to your fender. The covers are secured, both top and bottom, with an adjustable, high strength polypropylene rope that keeps the cover in place