The pressure-actuated valve from the center of the Prismo Aeropress Attachment. You need this if your Prismo leaks, or only needs low pressure to push coffee through.
 
(Sold in a set of 2)
 
What's in the box:
2 x Prismo pressure-actuated valve
 
NOTE: This is a repalacement spare part. Cannot be used without a PRISMO!