Derailleur hanger is a metal extension of the rear dropout through which a rear derailleur is mounted. If the rear derailleur is damaged, mostly likely the derailleur hanger could be damaged as well and has to be replaced. Its also recommended to carry a spare derailleur hanger when riding a mountain bike.
Below is a reference of compatibility list. On top of that, please always compare the geometry of your original derailleur hanger with that in the picture to make sure you are purchasing the right part.
Compatibility Reference:
(Note: because bike manufacturers keep bringing new models to the market, some models may not be listed here.)
Repalce GT part no. ATIDH0071,ATIDH0239 and ATIDH0246
Repalce KHS part no 276
Airborne:
Guardian
Seeker
Skyhawk
Delta CX
Goblin
Co-op:
REV 20 2018-19
REV 24 2018-19
Dahon:
QIX D8 2016-18
Garneau:
TRX-1 2013-16
TRX-2 2013-16
TRX-3 2015
GT:
Aggressor Comp: 2018-20
Aggressor Expert : 2016
Aggressor Pro
Aggressor: 2013-17
Avalanche Elite: 2016
Avalanche Series: 2006-16
Bump 26 inch: 2016
Hans Rey Trails: 2008
Karakoram: 2011-13
Laguna Pro Womens
Marathon Series: 2007-10
Nomad Series: 2007-16
Sensor Series: 2010-13
Stomper 24: 2018-20
Stomper Pro
Traffic Amp: 2017
Transeo 1.0: 2010; 2016
Transeo 2.0: 2010; 2016
Timberline: 2007-09
Verb Expert: 2016
Zaskar Series: 2006-16
Zum Series: 2006-07
Kestrel:
Yuma 2012-14
Kettler:
Six Fifty 700: 2014
KHS:
2012-2018 Aguila
2012-2013 Alite 1000
2012-2013 Alite 2000
2013-2019 Alite 24
2014 Alite 300
2012-2014 Alite 350
2012-2014 Alite 500
2014 DJ 24
2014 DJ 50
2013-2015 Six Fifty 600
2014-2015 Six Fifty 700
2012-2016 Tempe
2012-2015 Tucson
2013-2018 Winslow
2013 Yuma
Mongoose:
Argus