In-laws travelling 4yrs after getting B1/B2 visa

[IsItWorthTheTrouble]

Hi,
My in-laws got their visa (10-yr multiple) in april '2009 but their visit @ that time got postponed. They are now planning to visiting us this summer but I would like to know if there's any additional documentation other than a invitation letter that they 've to carry with them.

Thanks.

[qesehmk]

since they already have a visa - technically they don't need anything else to travel. Good luck w the trip.
Hi,
My in-laws got their visa (10-yr multiple) in april '2009 but their visit @ that time got postponed. They are now planning to visiting us this summer but I would like to know if there's any additional documentation other than a invitation letter that they 've to carry with them.

Thanks.