Modified Macintosh and Fildes pattern has all metal construction consisting of a S.S. Jar with a top flangs recessed for a thyroidal rubber sealing ring and a cover held in place by a strong bridge clamp. The cover is fitted with two needle valves for evaluation and a sachet containing a catalyst. A side arm on the jar is rovided for connecting to Semisolid Lucas Indicator. (The unit is supplied without Semi-Solid Lucas Indicator). Supplied complete with pressure-cum-vacuum gauge.