Excise querry

my client is of transformer manufacture now my querry is :

1.the item cetsh no. is 85042100 - transformer, 7204100 - waste and scrap of iron and steel , 74040019 - waste and scrap of copper 
now the question is rate is 12% than what will be notification number which we have to write in excise return.

Pls rply

Thnx in advance.