Ultimate stretch without compromising warmth for anyone who loves the feeling of unmatched freedom of movement. The Seek Amp 5/4 Back Zip features our ultimately stretchy Max_Flex outside lining. Key Features Toasty Warm:Quick drying Plasma_Plush 2.0 combined with Hot_Stuff 2.0 for the best combination of warmth and stretch. Epic Stretch:Limitless movement thanks to less panels and our stretchiest lining Hot_Stuff 2.0. Seam Sealing:Improved version of highly elastic neoprene tape securing every inch of lower body seams and highly stressed cuff area. Max_Flex: