SBI offers such a wide variety of fixed deposit schemes to pick from so the features are also varied. The features are as follows:

Tax benefits under section 80C
Extra interest of 0.25% payable to senior citizens
Loan and overdraft facilities of up to 90% of the deposited amount
Auto-renewal facility when a maturity period has not been defined
Linking of TDRs to saving / current account to allow periodic withdrawal of interest earned
Nomination facilities
Interest rates will remain the same as they were at the time of opening the FD despite of changes made to the scheme after the FD was opened. New interest rates will be applicable only on renewal of the deposit.
No limits on the amount that can be invested.

Eligibility -
Any individual, private or public limited company, Hindu Unified Family, trust, partnership firm or society is eligible to open a fixed deposit account with SBI.
In the case of individuals, the terms and procedure for opening a fixed deposit account with SBI is the same as that for the savings account.

The minimum and maximum periods for funds to be held with SBI vary with the scheme that you choose. As such the minimum period is 7 days and the maximum period is 10 years. The minimum and maximum periods for each of their schemes are:

SBI Tax Savings Scheme, 2006: 5 - 10 years
Reinvestment Scheme: 6 - 10 years
SBI MODS: 1 - 5 years
Recurring Deposits: 1 - 10 years
Annuity Deposit Scheme: 3 - 10 Years
SBI Flexi Deposit Scheme: 5 - 7 years