The term zone of possible agreement (ZOPA), also known as "zone of potential agreement" or "bargaining range", describes the range of options available to two parties involved in sales and negotiation, where the respective minimum targets of the parties overlap. Where no such overlap is given, in other words where there is no rational agreement possibility, the inverse notion of NOPA (no possible agreement) applies. Where there is a ZOPA, an agreement within the zone is rational for both sides. Outside the zone no amount of negotiation should yield an agreement.