FC transfer means your products are being transferred to a different fulfillment center. While these item are available for sale, the arrival date for a customer will most likely show 2 weeks or more in the future.
As you can see in the picture, the arrival date is saying march for the top seller while the competitor below whose units are not in FC transfer are available immediately.
Are units in FC transfer for sale?
Why are my units showing an arrival day 3 weeks away?