Offers and conclusion of a contract. 1. Offers All calculations and estimations made by Filmar are for reference only and they do not constitute an offer unless this has been expressly stated. The offers shall be prepared after a client has delivered a complete set of documents and information needed to carry out an order. Only a document referring to all essential elements of an order constitutes an offer. Any modification of an offer made by a client, constitutes a new offer and must be expressly accepted by Filmar. Offers are valid for the period of 30 days from the day of their publication, unless another term is indicated therein.