looking for long range UHF tag reader for Arduino UNO/MEGA

Hi Guys I am newbie working on RFID project, Long range UHF reader is required for Arduino. Any guidelines for buying UHF tag reader, tags will be passive or active tags. What do guys think if I buy ME6 Nano by Sparkfun and is there anyone who is using ME6Nano!!

-Should read multiple tags at a time (simultaneously)

Looking forward to the responses, Thanks Regards

Also posted on SE: https://arduino.stackexchange.com/questions/47179/looking-for-long-range-uhf-tag-reader-for-arduino

Downvoted already on SE. Probably for being a poorly defined problem.

Define “long range”.
Define “mutliple”.

Without that there’s no way anyone can make sensible suggestions.