The Aqua-Pure 69811-42 is a replacement sump for AP11T and AP101T. Clear sumps are great for visual filter inspection, but they wear out faster than their opaque counterparts. Replacing the Aqua-Pure 69811-42 every 5 years is recommended to avoid catastrophic failure. It's an easy and economical way to keep your home safe from water damage and keep your filter system in tip top shape. The Aqua-Pure 69811-42 is for Models AP11S, AP11T, AP12S, AP12T, AP26T, AP51T, AP101S, AP101T, AP102S, AP102T, and AP141T.