How to install pre-filter?

[Marconis]

I recently bought two Filter Max II Pre-filters to install on my intake in order to prevent sand from coming in my filter. For some reason, I cannot understand how to properly attach two together, although it says it on the back of the box I feel stupid lol, so does anyone know how to do it, in simplest terms?

http://www.americanaquariumproducts.com/PreFilter.html

That's it.

[roka64]

It's a pre filter sponge, is it possible that you have two sponges in one box? In this case, you only use one at a time.....Unless I am missing something....

[Marconis]

I am missing something too. NosVorax told me to order two, but I never asked why. Heh, maybe he'll chime in.

[Innovator]

I agree that I only see the need for an extra sponge so that one can be cleaned while the other accumulates debris.