instead of pos and maternode fbf has deposit. See OP.

you can lock your coins for a period of time, minimum 1month max 1year, it will give you interest on your deposited FBF.

100FBF locked for 1 month = 1.25% , at the end of 1 month the unlocked amount will be 101.25FBF
similarly you ll get following interest rates for the term you choose. Better than bank deposit.
Deposits:
Months    Interest Rate
  1             1.25%
  2             2.50%
  3             3.75%
  4             5.00%
  5             6.25%
  6             7.50%
  7             8.75%
  8            10.00%
  9            11.25%
 10            12.50%
 11            13.75%
 12            15.00%

Deposits work as a source of "minting" new coins besides mining.
when you lock your coins there is a 0.001FBF fee because your deposit gets included on the blockchain and will unlock at the block height specified on the deposit details