$ cat cards/eren-derdiyok-p20-2010/faq/completion-faq-23.md
How do I mark the Eren Derdiyok sticker as owned in my companion checklist?
card: Eren Derdiyok P20 (2010) · category: completion
[Concise Summary]
You can tick the checkbox next to code P20 in the interactive Checklist page. This updates your client-side localStorage state instantly, saving your progress on page reload.
[Structured Data Grid]
| Checklist Action | Check code P20 |
| State Storage Method | Browser localStorage |
| Progress Persistence | Persistent across tabs |
| Export Option | Copy Checklist string |
Detailed Investigation & Analysis
The companion checklist uses client-side storage to index your collected album assets. Ticking the checkbox updates your collection completion metrics. Avoid clearing browser data to prevent losing checklist records.
Additional notes for collectors: Ensure checklist entries are verified before confirming trades. Standard trade ratios are calculated relative to card popularity.
[Album Context Specs]
| Card Code | P20 |
| Official Name | Eren Derdiyok P20 (2010) |
| Estimated Value | $0.52 USD |
| Album Section | Switzerland (2010) |
| Completion Mode | Required Checklist Item |