Replacement Two Little Fishies PhosBan Reactor 150, Washer. Note: The Washer and O-Ring look similar. The Washer is flat and the O-Ring is rounded.
The Washer might be black or it might be clear. Either way, this Washer is very thin plastic. If the Washer you're replacing is rubber and 1/8" thick, you will need to get the Two Little Fishies PhosBan Reactor 150, NEW Washer instead.
