The Package Option Technique for counter offers is to give your counterpart a choice, i.e. a two pronged counter offer. The benefit of this type of counter offer is that the counterpart frequently picks one, as they are so busy concentrating on the two choices that they do not concentrate on the fact that they can choose neither one and make another counter offer. Another benefit is that the counterpart does not feel like they are being pushed into a corner by being forced to take one option, as they have two (or more) options, and they have the last word.
Be aware that there is a frequent response to this type of offer. The counterpart will take the best of both choices. If you are looking to close negotiations, give your counterpart a Package Option, but be sure you will be happy if they take the best of both choices. A related concept is giving people two choices when you want to get a any decision.
For a more detailed discussion on this topic, please go to http://createagreatdeal.com/principles/techniques-tricks/the-package-option-trick/.