Leases, Sales, Contracts, Conditions, Agreements or Understandings to Lessen Competition. It is unlawful for any person to lease or make a sale or contract for the sale of goods, merchandise, machinery, supplies, or commodities for use within the Commonwealth, or to fix a price charged for them, or discount from, or rebate upon, such price, on condition, agreement or understanding that the lessee or purchaser thereof shall not use or deal in the goods, merchandise, machinery, supplies, commodities, or services of a competitor or competitors of the lessor or seller, where the effect of the lease, sale or contract for sale, or such condition, agreement or understanding may be to substantially lessen competition or tend to create a monopoly in any line of trade or commerce in the Commonwealth. Source: 33 TTC § 303.