For quick prototypes and casts this is the product to buy. This is a polyurethane resin for casting and tooling. It has a 3-4 minute pot life and takes about 30 minutes to cure. It also has an unbelievably low viscosity so will find its way into intricate moulds. Supplied as a two-part kit, it's easy to use; just mix the resin and the catalyst 1:1 by weight, stir well for approximately one minute and pour immediately. Provides excellent detail and works brilliantly when cast into the value RTV Silicone. Unopened shelf life 6 months, opened shelf life 12 weeks.