This specification covers a plasticized, polyether-type, urethane (EU) resin and hardener which, when mixed and cured, produces elastomeric polyurethane products. This resin has been used typically for applications, such as electronic encapsulation or for casting parts and shapes, requiring exceptional flexibility down to -55 degrees C (-67 degrees F) where poor reversion resistance can be tolerated, but usage is not limited to such applications.