Finally, standard CDS contracts specify "deliverable obligation characteristics" that limit the range of obligations that a protection buyer may deliver upon a credit event. Trading conventions for deliverable obligation characteristics vary for different markets and CDS contract types. Typical limitations include that deliverable debt be a bond or loan, that it have a maximum maturity of 30 years, that it not be subordinated, that it not be subject to transfer restrictions (other than Rule 144A), that it be of a standard currency and that it not be subject to some contingency before becoming due.