This service will unlock any Samsung USA phone instantly. Please be sure to the appropriate model.
Some models such as T669 may return not found. If this occurs, you will need to use the Samsung Tmobile or Samsung AT&T 'Slow Tool' which will get the code from the manufacturer manually.
Update: From Thursday 30th June and until Tuesday 5th July, Samsung USA Instant service will work in 6<>24H instead of Instant. Samsung USA Slow methods are working normal.