RAMASWAMI, J.

This revision petition is filed against the order of the Tribunal setting aside the penalty levied under section 10(b) read with section 10A of the Central Sales Tax Act, 1956. The respondents are dealers registered under the Central Sales Tax Act. They are film producers and processors of cinema films. They purchased an Otis lift for Rs. 20, 630 on 30th September, 1960, by issuing C forms. On the ground that the registration certificate issued under the Central Sales Tax Act did not authorise the purchase of Otis lift by issue of C forms, the Joint Commercial Tax Officer, T. Nagar Division, initiated proceedings under section 10(b) read with section 10A of the Act. The respondents replied by their letter dated 9th May, 1967, that Otis lift purchased by them would come either within the class of articles mentioned in category (b) of the certificate of registration or under category (c) as accessories of plant and machinery necessary to execute the contracts for studio hire. In support of their contention that the lift was indispensable for the manufacturing process carried on in their premises and, therefore, it would come within the class of goods mentione