The Amazon Fire Keyboard can be used for all Kindle Fire HD models including the Fire HD 6 and 7, the Fire HDX and the Fire HDX 8.9. The keyboard does not support non-HD Kindle models, as of 2015.
The Amazon Fire keyboard features a full keyboard, trackpad and shortcut buttons. It attaches magnetically to the Kindle Origami case. The only other keyboard available for Kindle Fire is the AmazonBasics bluetooth keyboard, which also supports all Fire HD and HDX models. In addition, this keyboard can be used for Android devices running 3.0+ software versions. No keyboard is available for the original Kindle Fire or older model Kindle devices.