KT Tape KT Flex is specially engineered to provide a more effective, comfortable support for weak or injured knees. It features a 4-strip application system that provides target support for the inside and outside of both knees. It is water resistant and is comfortable to wear for up to 3 days. The KT Flex is for those who want extra support for the knee without the bulk and restriction of a stabilizing sleeve. The specially woven design comes blue and black in color and has a heat-activated latex-free adhesive.