An illegal tying arrangement requires the proof of four things. First, two separate products or services must be involved. In our case, cable television services are a completely separate product from a cable box. Second, the purchase of the tying product (here the cable service) is conditioned on the additional purchase of the tied product (the cable box). Showing that the seller (Cox) has sufficient market power in the market for the tying product (premium cable service) is the third step. This lawsuit has been filed in markets around the country where Cox is the main provider and in many instances the sole provider of premium cable services. The final piece that must be shown is that the alleged behavior has more than an insubstantial effect on interstate commerce in the tied product market. In our case, Cox’s insistence that Cox customers rent a cable box in order to receive Cox premium cable prevents thousands of potential customers from purchasing cable boxes from any source, severely restraining interstate commerce.