The various resorts of Anfi del Mar have fixed weeks as well as flexible weeks.

The resorts Anfi Beach Club und Club Puerto Anfi have almost only fixed weeks. A fixed week means that the timeshare holder has the right to use the week XY in apartment YX each year.

The resorts Club Monte Anfi and Club Gran Anfi have almost only flexible weeks. Fixed weeks are the exception for favoured seasons. Flexible weeks means that the timeshare holder has the right to use one week in a certain apartment type, e.g. 1 SZ (one sleeping room). In this case the timeshare holder has to inquire the resort for the wanted week and gets in return a free apartment. Timeshare holder are flexible and can travel each year at a different week and period of time.
It may be that the period of time in which the timeshare holder can decide about a week is constrained, e.g. at Christmas and Sylvester, or simply booked out.