The Laguna PT1503 is the correct replacment foam kit for the following:
The Laguna Pressure-Flo Foam Kit for PT1502 - 4 pack is a replacement foam kit for the Laguna Pressure-Flo 1400 and 5000 that contains four replacement foam filter rings. This replacement foam filter is constructed with very porous material that removes debris from pond water and increases clarity. Laguna foam filters can be easily installed and maintained, and should be replaced annually.
Laguna Pressure-Flo Foam Kit for PT1502 - 4 pack specifications: