The Judgment of the Court was delivered by

SMT. SUJATA V. MANOHAR, J. - The applicants Uni Apex Alloy Products Ltd., Bombay, manufacture, inter alia, alloy castings and reformer tubes. They have a factory at Thane. The applicants entered into a contract dated 11th April, 1975, with Gujarat State Fertilizers Company Limited, for fabrication, supply and erection of 208 reformer tube assemblies for the conversion of the ammonia plant of the Gujarat State Fertilizers Company Limited at Baroda from a cold bottom system to a hot bottom system.

2. The applicants are holders of a registration certificate both under the Central Sales Tax Act as well as the Bombay Sales Tax Act. On 17th November, 1976, the applicants applied to the Deputy Commissioner of Sales Tax, Bombay, under section 52 of the Bombay Sales Tax Act seeking his determination as to the nature of the transaction represented by the said contract of 11th April, 1975. They annexed a provisional invoice dated 30th April, 1976, for Rs. 49,451.70. This invoice was in respect of one reformer tube assembly, exclusive of tube top assembly, catalyst support assembly and other fixtures to be supplied and billed later. It was ch