An extremely soft and flexible silicone mold-making rubber used for items with deep undercuts and negative drafts. High Strength 3 is great for 1-piece molds, reducing seam lines and the need for 2 piece molds. Splitting the mold is also an option for severe undercuts where relief is required. More Info: Alumilite Corp-High Strength 3 Liquid Mold Making Rubber: Pink. Perfect to use when you have the deepest undercuts! The high strength rubber is thin enough that it will pick up all the detail of your original without the need for vacuum or pressure casting. This package contains one pound of flexible mold-making rubber mix. Complies with ASTM D 4236-94 and LHAMA. Made in USA.BICW