Section 2--207. Additional Terms in Acceptance or Confirmation

(1)  A  definite  and seasonable expression of acceptance or a written
  confirmation which is sent within  a  reasonable  time  operates  as  an
  acceptance  even  though it states terms additional to or different from
  those offered or  agreed  upon,  unless  acceptance  is  expressly  made
  conditional on assent to the additional or different terms.
    (2) The additional terms are to be construed as proposals for addition
  to  the  contract.  Between  merchants  such  terms  become  part of the
  contract unless:
         (a) the offer expressly limits acceptance to  the  terms  of  the
             offer;
         (b) they materially alter it; or
         (c) notification  of  objection to them has already been given or
             is given within a reasonable time after  notice  of  them  is
             received.
    (3)  Conduct  by  both  parties  which  recognizes  the existence of a
  contract is sufficient to establish a contract  for  sale  although  the
  writings  of  the parties do not otherwise establish a contract. In such
  case the terms of the particular contract  consist  of  those  terms  on
  which the writings of the parties agree, together with any supplementary
  terms incorporated under any other provisions of this Act.