There are three different types of Blocking Plugs:

  1. Black Blocking Plugs come standard in all Berkey Light® systems and some stainless steel systems. The black plugs are made of FDA approved Buna rubber.
  2. Off-White Blocking Plugs may come with the Berkey Light® and some stainless steel systems. The off-white plugs are made of food grade M18 pure gum rubber.
  3. White Screw-Type Blocking Plugs are used in some stainless steel systems. These come with a nut, a screw and two clear washers. The nut and screw are made of Polypropylene. The washers are made of food- grade silicone.

Please keep in mind that the water in the bottom chamber of your unit will not touch any of the Blocking Plugs. The water will be filtered/purified before it reaches the bottom chamber.