It is more likely that you'll come across tours that include optional extensions to one or the other site.

The lease would run for 65 years with two optional 16-year extensions and a possible rent increase after 10 years.

Israeli law allows 28 days to form a new government, with an optional two-week extension.

Each written request for an optional three-month extension must comply with the requirements described in Announcement 2011-71.

The optional extension is not part of the Birthright trip, and the participant is in that time like any tourist.

In 2004, he signed a contract to extend his tenure from 2005 to 2008, with an optional two-year extension at the end of that time.

It consists of a 20km loop with an optional 10km extension.

The second phase may last no longer than 59 days, including optional 14-day extension.

An optional two-year extension, if exercised, would bring the total billings to $150 million.

An optional extension gives selected user groups priority when edit conflicts occur.