Section 2--306. Output, Requirements and Exclusive Dealings

(1)  A term which measures the quantity by the output of the seller or
  the requirements of the buyer means such actual output  or  requirements
  as  may  occur  in  good  faith,  except  that  no quantity unreasonably
  disproportionate to any stated estimate or in the absence  of  a  stated
  estimate   to  any  normal  or  otherwise  comparable  prior  output  or
  requirements may be tendered or demanded.
    (2) A lawful agreement by either the seller or the buyer for exclusive
  dealing in the kind of goods concerned imposes unless  otherwise  agreed
  an  obligation by the seller to use best efforts to supply the goods and
  by the buyer to use best efforts to promote their sale.