The majority who receive an exemption from the obligatory army service are Jewish women from the Religious Zionist sector, and they receive it by declaring religious observance, as they maintain that a large number of religious observances for women cannot be upheld in the military, such as dress codes and modesty issues. However, there are also a small number of men who serve in Sherut Leumi. Volunteers are between the ages of 18 and 21. Service typically requires working 30–40 hours/week over 12 to 24 months. Volunteers have the option of doing either one or two years of the National Service. Not all volunteers are Israeli citizens. It can be done on a tourist visa, and the volunteer will later receive a special volunteer visa that lasts as long as the person will be doing their service.