[imnuts]

The radio unlocker will allow you to use unlocked radios on your Sprint phone. Not sure if it really affects other carriers or not. It's meant so that you can use AT&T and/or T-Mobile with it. Sprint's TP2s came SIM unlocked already, but the radio locks out the use of the domestic carriers, hence the radio unlocker to allow you to use domestic carriers.

SIM unlocker is so that you can use any SIM in the phone. You can likely perform the SIM unlock for free just by calling your carrier and asking them for the unlock code, though some carriers are less willing to do this for you.