Extang Endure ALX - 99-16 F250/350 6'9" Model 80720Extang Endure ALX 99 16 F250 350 6'9" Model 80720 From tireless engineering and a relentless pursuit for perfection comes a low profile bed cover designed to function like no other the Endure ALX from RealTruck. With a flush mounted design, the Endure ALX creates a seamless, polished exterior appearance when closed while delivering highly functional full bed access when open. The Endure ALX features four patented EnduraShield TPO coated panels,