ProOne was bought out by Culligan, and they are shutting down the ProOne brand. We do have other filters that will work in the systems. Here is the link to them.

Aquacera CeraMetix Gravity Replacement Filters

The ProOne® G2.0 series filter is the only gravity filter that bears the distinguished NSF/ANSI-42 component certification. Independently lab tested for performance in the reduction of over 200+ contaminants including heavy metals, fluoride, pesticides, herbicides, chlorine, chloramines, pharmaceuticals and more! Ideal for use with most natural potable water sources. Available in 4 sizes to fit most other gravity filtration systems.

Advanced features of the ProOne® G2.0 series filter include:
-“All-in-one” filter technology. NO add-on filter required for fluoride reduction
– Infused bacteriostatic outer ceramic shell and proprietary carbon-based granular media inside the core of the filter.
-No priming required
-Cleanable, reusable, can be stored in a cool dry place when not in use
-Does not need to be kept saturated when not in use
-Available in 4 sizes, 4”, 5”, 7” and 9” tall by 2.75” diameter
-Improved flow rates
-May contain coconut