The 171st mitzvah is that we are commanded to give a half shekel1 every year.

The source of this commandment is G‑d's statement2 (exalted be He), "Each man shall give an atonement offering for his life," and, "[Everyone included in the census] shall give [a half shekel.]"

It is clear that women are not obligated in this mitzvah, since the verse says, "Everyone included in the census" [and only men were in the census].

The details of this mitzvah are explained in the tractate devoted to this subject, i.e. tractate Shekalim.

There it is explained that this mitzvah applies only when the Holy Temple is standing.