These urethanes are highly filled, super hard and very fast setting.They are low exotherm, have low shrinkage.Ideal for Foundry Patterns, Industrial molds, fixtures, Prototype vacuum form molds and prototypes. Gel time 6-10 minutesDiemold time 60-90 minuteshardness shore d: 85Specific Gravity 1.78 Compressive strength psi 7400 PSI. !!!! any questions please ask. I have 20 one gallon kits available and would be open to offers on the whole lot if interested. Thanks,