These cartridges can be inserted into the top of the Interpet UGF uplifts.
Replace every 8 weeks or when water becomes discoloured.
Recharge every 4-6 weeks by soaking in a salt solution.
They ONLY fit the Interpet range of under gravel filters.
One fits the 18" Filter.
The other fits 24", 30", 36" and 48" Filters.
