Mailing it help

I live in Phoenix, so I will mail it to Phoenix lockbox? I will UPS mail express so which one will use PO box or SKY harbor?

Use sky harbor... even though honestly, first class mail would suffice since its pretty much the same city >.>

I live in Phx. I'm mailing mine to sky harbor on monday.

I'm confused. So there is two different lockbox facilities depending on which mail service we use?

which addresses are ya'll using? U.S.Postal Service or USPS Express Mail/Courier?

Yep.

http://www.uscis.gov/portal/site/usc...0045f3d6a1RCRD

Does anyone know the difference between those two mail services? Is one a lot more expensive than the other?

^^

Yes it is. (https://www.usps.com/business/prices.htm)
Express service is about $18.00 because you're also purchasing the insurance along with it, and it is an overnight delivery. If you're using Priority mail, it's only about $5.00, no insurance (unless you buy separately) and has 2-days delivery time. However, if you already live in AZ, Priority mail will be ok. Just make sure you have it registered when you mail it.

^Yes, the express/courier is more expensive because it gets your package delivered there quicker; and usually requires a signature (unless you waive it)

is it recommended to waive the signature in case nobody there is authorized or able to sign at the time the packet is delivered, or not? Are you guys waving it?