The Chemex filter is a thick, folded paper filter that's designed to fit into the Chemex coffee brewer. The thicker paper filter helps filter out oils in the coffee along with the coffee grounds and helps create a slow, steady drawdown. 

When using the filter, align it so the thicker side aligns with the spout, so that the pouring spout can stay free and open for airflow. 

This is a pack of 100 filters, and is designed to fit the 8-cup Chemex that Ruby offers for sale online. They also fit 6 cup Chemex brewers.