We shall only have the obligation to perform if and when the customer fulfilled all its obligations required for performance, especially all technical and contractual details, pre-work and preparations. We shall be entitled to exceed the agreed deadlines and terms of delivery by up to one week. Only after expiry of this period can the customer terminate the contract after having set a grace period of 4 weeks. Unless expressly otherwise agreed upon in writing, terms of delivery shall be without obligation. However, we will make an effort to adhere to promised periods of time.