ISOLATOR insulating sleeve is manufactured using high temperature ceramic fibres. It might be used for both cast and cast iron. It is recommended primarily for large-sized sprue, in which effective insulation of sprue is needed rather than exothermic reaction in sleeve. Effective insulation of sprue might prolong the process of crystallization in the sprue by to 35%. Using this sleeve results in decreasing heat losses in the sprue, which ensures a more favourable shape of contraction hollows, thereby, a greater metal yield.