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 UCC 2-612 discloses the rights of the parties to installment contracts:

    '(1) An 'installment contract' is one which requires or authorizes the delivery of goods in separate lots to be separately accepted, even though the contract contains a clause 'each delivery is a separate contract' or its equivalent.

    (2) The buyer may reject any installment which is non-conforming if the non-conformity substantially impairs the value of that installment and cannot be cured or if the non-conformity is a defect in the required documents; but if the non-conformity does not fall within subsection (3) and the ...