Small scale industry exemption: units under prior-year turnover threshold choose exemption or opt to pay duty and claim cenvat. Eligibility for SSI concessions depends on prior-year turnover below the prescribed threshold. Manufacturers may either avail an excise exemption up to the annual ceiling and claim Cenvat only after crossing that ceiling, or elect to forgo the exemption, pay normal duty and claim Cenvat; the latter option must be notified in writing with specified particulars and, once made, is irrevocable for the financial year. Clearances are clubbed for determining eligibility where effected from the same factory or across factories of the same manufacturer, with limited exceptions for separately funded and managed units.