zangra says

These cotton coffee filters are a good ecological alternative to single-use paper filters.
These are fully compatible in No. 4 cone shape.

Care
Wash before first use
For simple cleaning: wash with clear water.
For a complete cleaning: machine wash at 40°C (with the use of sodium percarbonate)

Eco-friendly ?
* Washable and reusable product
* Durable product
* Made of organic cotton

Technical description