In its unvulcanized form, the 800 Series compound is tackier than other compounds, making it a good choice when extensive build-up in mold preparation is required. This is a mold compound with very high dimensional stability that results in uniform shrinkage. Parts are rendered with little or no die parting lines. while the mold set retains maximum flexibility and tear strength. It’s a highly versatile compound, suitable for producing tiny, highly detailed parts as well as larger, highly modulated sculptured pieces. Every rubber mold set consists of two 1/2" thick sections, and each section has 10 laminations.The 800 Series is a sulfur cure rubber.