Vinylester Resin 555 is a Premium Vinyl Ester, thixotropic, designed for fabrication/Repair of small to large FRP parts at an ambient temperature. Very high strength, High heat distortion temperatures and excellent secondary bonding. 555 is pre-promoted for curing at room temperature with the addition of methyl ethyl ketone peroxide (MEKP) initiator. 555 is designed to be used with both the spray-up and hand lay application technique. MEKP sold separatly. 3 MONTH SHELF LIFE.