Art. 65 CISG
(1) If under the contract the buyer is to specify the form, measurement or other features of the goods and he fails to make such specification either on the date agreed upon or within a reasonable time after receipt of a request from the seller, the seller may, without prejudice to any other rights he may have, make the specification himself in accordance with the requirements of the buyer that may be known to him.
(2) If the seller makes the specification himself, he must inform the buyer of the details thereof and must fix a reasonable time within which the buyer may make a different specification. If, after receipt of such a communication, the buyer fails to do so within the time so fixed, the specification made by the seller is binding.
The Secretariat Commentary on Art. 61 of the 1978 New York Draft, predecessor to Art. 65 CISG, gives insight into the drafters' unterstanding on the eve of the 1980 Vienna Diplomatic Conference.
Overview of case law on Art. 65 CISG: UNCITRAL Digest
The UNCITRAL Digest on the CISG can be used as a starting point to discover the relevant case law on this article.