The code is: "X2M0A1S7"
Redeem on the main BSGO website seems to work the best.
Content:
* 1 Divine Inspiration
* 6 Alpha Map Parts
* 6 Beta Map Parts
* 6 Gamma Map Parts
* 7 days Merit Cap-Booster
The code is valid from December 24th, 2017 until January 15th, 2018.