Waterdrop AP431 Replacement Cartridge for Aqua-Pure AP431 Hot Water Scale Inhibitor for AP430SS, Prevent Scale Accumulation and Protect Water Heaters, Pack of 1

Super easy to install and prolongs the life of the heater and restores water flow.

Excellent product as promised

It fits perfectly without leaking on my water heater and it seems to be working just fine. Good price and so far good performance.

Like others noticed, when you shake the filter, there seems to be less material in the filter vs the original. No idea if that matters. The filter installs just like the original and had no leaks.

Easy to install and works great on my tankless hot water heater.

There's a whole lotta variables that determine whether these will work for your system requiring a whole lot more water quality chemistry than I ever learned in school (that was a joke), but when you get it right, the calcium carbonate (whitish grey chunky stuff) on your faucets go away like magic . . and these last us nearly a year before that gunk starts coming back . . puttem just within 4' from the input side of the water heater is best for the pipes in your system. Too much use of these can cause premature pipe failure, too little and they don't work, and the pipes clog up . . you oughta consult someone who actually knows what they are talking about before you use, em, or maybe even consult the I-Ching, not sure, but under the right circumstances, like I said, bye bye calcium carbonate . .

Shipped fast and as described, work well

it threaded into the aqua pure ap431 adapter. Only problem. the threads on the filter were messed up. Had to fix them for it to work.