Using Smooth-On's exclusive "V-Polymer" technology, VytaFlex urethane rubbers offer superior physical and performance properties designed for casting concrete. VytaFlex urethanes feature convenient 1:1 (by volume) mix ratios. Vacuum degassing is not necessary and VytaFlex rubbers cure with negligible shrinkage to a durable rubber that will last in production.Vibrant colors can be achieved by adding So-Strong Color Tints, available from Smooth-On. VytaFlex 20- MIX RATIO 1:1 by volume, Pot Life: 30 min., Demold Time: 16 hours, Cure Time: 24HRS, Shore A Hardness: 20, Color: Clear Amber