Cenvat credit eligibility clarifies permitted inputs, key exclusions, timing for claiming credit and reversal obligations. The note sets out that Cenvat credit is available only for goods qualifying as inputs under Rule 2(k), enumerates six explicit exclusions (including fuels and structural works materials), and explains that eligible goods used within factory premises, for output services, for warranties, or for captive power are generally creditable. It summarizes Rule 3 obligations to repay credit where inputs are removed, written off, or diverted, and Rule 4 timing and job-worker conditions that permit credit when inputs are sent out and returned within the prescribed period, with entitlement to reclaim credit on subsequent receipt.