> For the complete documentation index, see [llms.txt](https://meetway.gitbook.io/meetway/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://meetway.gitbook.io/meetway/gameplay-nfts/cds.md).

# CDs

CDs are our special pieces of jewelry that helps users to use the Music-to-Earn feature when exercising.

### **TYPE & LEVEL:**

The user can unlock the CD Socket once their Sneaker/Bicycle reaches a certain level and can enhance their Sneaker/Bicycle Attribute by inserting the corresponding CDs into the socket (each CD will correspond to those sockets) 

There are four types of CDs, one for each Attribute:

* Yellow: effective (happy, euphoric music genre) 
* Red: comfortable (soft music, lofi) 
* Green: good luck (popular music) 
* Purple: recovery (instrumental)

Users can upgrade their CDs by burning **token (MWT)**, and combining 3 CDs of the same level and up to a higher tier (i.e. 3 tier 1 CDs into one tier 2 CD). 

**MET** will also be required to level up CD from level 4 onwards. 

Note: Upgrade CDs at low level may fail