Raidzap Flex: use for the baitfish flies where a more soft and flexible and rubbery head is desired. Can be used for the flyline, where a thin layer is glued on top of the loop to strengthen the loop. Raidzap Flex is crystal clear - cured in seconds and 100% tack free surface, Extremely soft and flexible, bonds to silicone, rubber and foam. Does not crack or peel during compression. Raidzap Flex Thick is developed for those who want thicker UV resin in flex mode from Raidzap. RaidZap Flex Thick allows you to build incredibly durable heads, bodies and carapaces in very minimal time. "oeFlex Thick" has double the viscosity of our standard flex UV resin which reduces the capillary action and slump when working and shaping.A thicker resin needs more time for curing with a UV flashlight.