if you intend visiting usa -homeland security , page-30

Michinyon,

Obviously this "green card" serves some purpose because they will not let you enter the U.S. unless it is presented with your passport.

Just so others can understand fully what is written in small print on the reverse side of this card:

Departure Record
Important - Retain this permit in your possession;
You must surrender it when you leave the U.S.
Failure to do so may delay your entry into the U.S.in the future.
You are authorized to stay in the U.S. only until the date written on this form. To remain past this date, without permission from Department of Homeland Security authorities,
is a violation of the law.
Surrender this permit when you leave the U.S.
- By Sea or air, to the transportation line;
- Across the Canadian border, to a Canadian Official;
- Across the Mexican border, to a U.S. Official.
WARNING: You are authorized to stay in the U.S. for 90 days or less. Violation of these terms will subject you to deportation.
Any previous previous violations of this program,including having previously overstayed on this program without proper
DHS authorization, will result in a finding of inadmissibility as outlined in Section 217 of the Immigration and Nationality Act.