Amazon has put up product pages for the standalone version of the Mad Catz Rock Band 4 Wireless Pro-Drum Kit. If you are interested, you can preorder the music accessory with the following links from the shopping website: PlayStation 4 version and Xbox One version. You can also check out what the kit looks like with our media gallery located below this paragraph.
As you can see above, the Mad Catz Rock Band 4 Wireless Pro-Drum Kit comes pre-installed with the cymbal expansion. By using this plastic instrument in the game, you will be able to unlock pro mode, which is the most challenging difficulty setting available.
Rock Band 4 came out in 2015 on the 6th of October for the two current-gen consoles in the North American region. DLC packs from the previous installments can be transferred from the Xbox 360 to the Xbox One as well as from the PlayStation 3 to the PlayStation 4. Harmonix teamed up with Mad Catz to distribute the software product as well as the music accessories.
If you are looking for a drum kit to go along with Rock Band 4, you might want to check out the upcoming Wireless Pro-Drum Kit from Mad Catz, which is expected to come out on the 29th of January in 2016.