Smooth-on Foam It 10 Trial Unit - (more than enough to fill a hollow head) FOAM-iT! 3, 5, 8, 10, 15 & 26 are expanding water blown polyurethane foams in 3, 5, 8, 10, 15 and 26 pound densities. FOAM-iT castable urethane foams will expand many times their original volume when mixed and poured. Developed for a variety of industrial and special effects applications, these casting foam products can be pigmented to achieve various color effects. FOAM-iT! foams are especially useful as reinforcement for hollow castings! GREAT FOR MAKING PROPS! FOAM-iT! 10 - 1A:1B by volume - approx. 6X expansion