X55 is a further addition to the range of PBI fabrics that combines high mechanical strength with all of the proven benefits of PBI. Brochure Where to Buy WHY CHOOSE X55? X55 fabric is an extremely strong PBI fabric. It delivers all of the proven benefits of PBI fabrics with excellent tensile strength and resistance. X55 is extremely durable and maintains its good looks and feel after extensive washing. X55 is available in gold and cognac.