In a legal action by Puff Promotionals against Tracy, Puff alleged that it had entered into a written contract with Tracy for the purchase of stain material which Puff intended to use in manufacturing products. Puff further alleged that Tracy failed to deliver the materials as promised. At trial. Mason testified that he worked in the Puff Promotional legal department and that he negotiated the contract. He stated further that although the original and all copies of the contract had been destroyed in an office fire, he knew the substance of its contents. Is Ma- son's testimony about the contract admissible at trial?