quick question, How can i find out what bands are supported?

For instance is there any app that can tell me the 4g bands that my phone supports.

this is my phone.

(bootloader) version: 0.5
(bootloader) version-bootloader: 3.18.0.0000
(bootloader) version-baseband: 4.0.U606061@41216A
(bootloader) version-cpld: None
(bootloader) version-microp: None
(bootloader) version-main: 2.22.401.5
(bootloader) version-misc: PVT SHIP S-OFF
(bootloader) meid: 00000000000000
(bootloader) product: m8_ul_ca
(bootloader) platform: hTCBmsm8974
(bootloader) modelid: 0P6B10000
(bootloader) cidnum: 11111111
(bootloader) battery-status: good
(bootloader) battery-voltage: 0mV
(bootloader) partition-layout: Generic
(bootloader) security: off
(bootloader) build-mode: SHIP
(bootloader) boot-mode: FASTBOOT
(bootloader) hbootpreupdate: 11
(bootloader) gencheckpt: 0

is there anyway of finding out the supported 4g bands with perhaps an app I've spent about an hour going through the play store, but have yet to find anything that will tell me this information, I'm thinking of flashing a eu ruu to the phone. This is how the phone came out of the box apparently its US at&t, however it came with an eu mid and was supercid and soff out of the box, very odd.