I have been in the hobby for several years and out of all the filters I have used these are the best. They are cheap to rum, take on a good size bio load, safe for babies of all kinds, and also create a food source for shrimp. Couldn't ask more of any filter.
Fits perfect in my 20L. Fast shipping, great product!
Matten Filter - 20 Gallon Long
Setting up several aquariums and ordered foam sheets and made my own matten filters. Ordered 1 from Flip Aquatics to see how they compared and liked theirs so much better that when set up 20L I went back to them to order. Really good quality product.