Ec2 Instance type: What is the difference between "Free tier available" and "eligible" ?

Hello,

Please look at this link https://aws.amazon.com/free/?all-free-tier.sort-by=item.additionalFields.SortRank&all-free-tier.sort-order=asc&awsf.Free%20Tier%20Types=*all&awsf.Free%20Tier%20Categories=*all

Free Tier Available: This means that the instance type is available to be used within the AWS Free Tier. The Free Tier provides customers with a certain amount of usage for AWS services each month at no charge. For EC2 instances, this typically includes a specific instance type and size that can be used for free within certain limits, such as a certain number of hours per month. If an instance type is "Free tier available," it means you can use that instance type within the Free Tier limits without incurring additional charges.

Free Tier Eligible: This means that the instance type is eligible to be used within the AWS Free Tier, but it may not be currently available for new accounts or regions. AWS periodically updates its Free Tier offerings, adding new instance types or changing the eligibility of existing ones. If an instance type is "Free tier eligible," it means it meets the criteria to be included in the Free Tier, but its availability may vary depending on factors such as region or account status.