An IR1 visa is an immigrant visa for foreign nationals who are legally married to a U.S. citizen and have been married for more than two years when their green card is approved. The IR1 visa is also known as the "immediate relative" visa because the spouse can apply for permanent residency immediately after entering the United States. The IR1 visa holder doesnt need to remove conditions and will have ten years before they need to renew their permanent resident card.

On the other hand, the CR1 visa is a conditional residence visa that is available to foreign spouses who have married their partner recently. This visa is granted on the condition that the couple stays married for at least two years after which the foreign spouse can then transition to an IR1 visa. If the couple gets a divorce or breaks up before the two years on the CR1 visa are completed, then the foreign spouse will be returned to their home country since their status will not be valid anymore.

Overall, both the CR1 and IR1 visas are designed for foreign nationals who are legally married to U.S. citizens and want to travel and move to the United States. The CR1 is a conditional marriage green card, valid for two years, while an IR1 is a permanent marriage green card, valid for ten years.