The Solarez Flex fly tying resin is a low odor, quick curing resin that retains some flex when cured and it will not feel "tacky" when it is cured with a high quality UV light. FLEX Formula - Flexible finish for swimmers, flex parts - could be used as a wader repair - Great for coating knots for strength - Viscous formula, easier to work with Usage tip: Apply in shade. Irradiate with intense UV light for FIVE SECONDS. Wait 15 seconds. Irradiate again for FIVE SECONDS. Wait. Do this a few cycles. Complete with 2 minutes continuous UV light. This technique will reduce heat & shrinkage. The FLEX formula requires more light than the THIN, MEDIUM or THICK. This technique will reduce heat & shrinkage.