REQUISITES:
a. Both parties must be mutually creditors and debtors - in their own right and as principals
b. Both debts must consist in sum of money or if consumable , of the same kind or quality
c. Both debts are due
d. Both debts are liquidated & demandable (determined)
e. Neither debt must be retained in a controversy commenced by 3rd person & communicated w/ debtor (neither debt is garnished)