PIN code acts as pass cord for your Air SIM and is initially set to "0000". If you type in wrong PIN three times in a row, the device will be locked, and you need a Personal Unlock Key(PUK) to unlock your device. Many devices disabled SIM Pin feature so often times, you do not need to deal with PIN code.
The PUK will be different in each operator so please contact support with your IMSI for the SIM you need PUK for.
Please note, by selecting the Air SIM on our User Console and Clicking on "Contact US" under "Support", IMSI will automatically appear in your new ticket.