Tying arrangements often increase welfare by promoting product quality and protecting the supplier\u27s goodwill in the tying product. When the tying product works effectively only with ancillary materials or accessories or services of a particular kind or quality, its supplier can assure the requisite quality of the ancillary product only by supplying that product itself. The cost savings defense and the defenses of quality control or good will are the most widely recognized and accepted tying defenses. One characteristic of manufactured products is differentiation among the offerings of various brands. This in turn produces a need for more specialized provision of such things as supplies, aftermarket parts, and service, thus requiring fir...