Step 1: Understand types of debentures Redeemable Debentures are repayable at the end of a fixed period or in installments during the company's lifetime. Perpetual Debentures have no fixed maturity and are not repayable. Secured Debentures are backed by assets but may be redeemable or perpetual. Specific Coupon Rate Debentures refer to the interest rate, not repayment terms. Step 2: Conclusion
Therefore, debentures payable after a specific period or in installments are Redeemable Debentures.