FCC certification - certifies that the electromagnetic interference from the device is under limits approved by the FCC.
CE certification - indicates compliance with EU legislation of a project (required for European countries).
RoHS certification - indicates compliance with testing when it comes to lead, cadmium, mercury, hexavalent chromium, etc.
These single USB port and dual USB port adapters are UL Listed (Underwriters Laboratories - leader in product safety testing and certification), so you'll have piece of mind that these items are safe and will work perfectly.