What are the plug-caps made of?

There are three different types of blocking plugs:

1. Black blocking plugs are supplied as standard with all Berkey Light water filters and some stainless steel models. The black plugs are made from FDA-approved Buna rubber.
2. Off-white sealing plugs (rubber cork) are available for the Berkey Light models and some stainless steel models. The off-white plugs are made from food-grade M18 pure natural rubber.
3. White locking plugs (bolt and nut) are used in some stainless steel models. These are supplied with a nut, a bolt and two transparent rings. The nut and bolt are made of polypropylene. The rings are made of food-grade silicone.

Please note that the water in the lower chamber of your water filter will not come into contact with any of the blocking plugs. This is because the water is filtered before it reaches the lower chamber.