Upon purchase, you'll receive TWITCH account.
Link it to your game account to claim the following items: 

1. x23 Legendary cases 
2. x33 Rare cases 
3. x46 Common cases

NOTE: 
!!! Claim items promptly post-purchase; they may expire.
!!! Unlink the Twitch account once all items are collected.
!!! Items hidden after 6 months are still claimable.

These items can only be obtained once per account. You will only receive items that you have not received before. Items may take up to 8 hours to arrive due to poor server performance.