All the below is based on Singapore Govt Treasury Bills, part of Singapore Government Securities.
This is the safest type of instrument especially if the Treasury Bill is issued by our Government. In general, this is something which is considered to be risk-free as it means borrowing our government money. Minimum investment size is $1K depending on where it's being sold.
Such investment instrument is issued on a discount on its maturity value by our government. The investment period is 3 mths and 12 mths. Liquidity is available unlike fixed deposit, they can be sold before maturity. It's just a matter on how much interest you'll get from such sale. But due to the low risk involved, there interest rate is not very high.
The interest aren't very high according to the statistics I've seem today. You may want to put them in those higher interest rate banks instead.