The Dual Media radios in Explorers (Cassette/CD combo) are rated at 80 Watts rms with Premium Sound. In the Mach Audio System, the system is rated at 145 Watts rms, 290 Watts peak.
If you have the Mach Audio System, your radio will have an RDS (for Radio Data System) button on it. That radio is made for Ford by Pioneer. The Mach system includes a subwoofer enclosure and SW amp in the RH rear quarter trim. If you have a storage bin there, you do not have a Mach Audio System.
If you have the Premium Sound system without Mach, the radio looks similar, but does not have RDS. That radio is made for Ford by Visteon (formerly Ford Electronics).
The factory six-disc CD Changer is made for Ford by Clarion.
Regards,
Jeff