“If you own one of these waterless urinals, Sorry, You need to use this cartridge, its the best at catching the urine salts and keeping them from clogging the 1/2 inch drain below the cartridge, In high use area's I recommend changing them out about every 3- 4 months. Expensive, but the cheaper ones allow the salts to overflow into the drain system, building up on the piping until they clog up. University with 100 + Waterfree Urinals Plumber”