This is NOT 2G data as some are implying. You use whatever 3G/4GHSPA connection and the data is THROTTLED to 128Kb/sec or so. This is HECK of a lot more reliable than EDGE/2G data. So no need to select 2G mode; just stick with 3G/4GHSPA and on T-Mobile's APN going BACK to T-Mobile for data they will throttle data (unless you pay for the per day/week/etc full perf packages)

This is a screaming deal.

SEPARATE ITEM: Another hint; the Samsung LTE hotspot for T-Mobile account users (new one) DOES NOT have free data BUT you can buy the same priced data packages for intl - that product NO longer requires a monthly fee for casual use. Used to be $10 usd a month now you get an "automatic 10 USD credit a month" with that device. Granted you have to pay for HW on terms or up front, but great option if you have others traveling with you and want to give them data without renting a hotspot - to be honest the 500MB for 50 USD is a good deal if you don't want to deal with local SIM cards.