These are a great filter medium. I like that you reuse the frame and just put new mesh and charcoal on, saving money and creating less waste than traditional replaceable filters.

Pros: Works great, saves money

Cons: none

I use these in one of my filters. They're easy to replace and are quite effective filters. I change mine monthly and have not had any problems with these filter cartridges.

Pros: easy to use

Cons: none

This is what my mom uses in her tank and they work really well. Her tank stays fairly clean even when she doesnt take the time to clean it.

Pros: works really well

Cons: none

I used these on my power filters. it is easy to take off the old and put the new clean one on. They are very effective.

Pros: Very effective

Cons: none

You get more for your money when you assemble them your self, but they are a little messy. Only takes a few minutes.

Pros: little messy

Cons: not as fast as pre-assembled