HSDPA Frequency

I am looking to buy a phone that says it has 2G in the right frequency bands for AT&T. But, for 3G it says "HSDPA 850/900/1900/2100" and for 4G it simply says "LTE Band".

My question is: Will this phone work as 3G? And, without knowing the specific LTE Bands, can you assume it works as 4G LTE on the AT&T network? (The phone is a Bluboo Maya).

Thanks so much for your help!

Questions