These O-rings are used to seal between the two halves of our Lightweight Easy-Clean Dry Sump Tanks, Part No. 1256-200, 1256-201, and 1256-202.
Note: These O-rings do not fit Easy-Clean tanks manufactured prior to 2010. Tanks can be identified by the lower outlet. Early tanks have the outlet fitting very close to the bottom of the tank, with a straight pipe inside sitting parallel to the tank floor. Later tanks have the outlet fitting several inches above the bottom of the tank, with a curved pipe leading from the fitting to the floor of the tank.