100% brand new and high quality Color: Blue Quantity: 4 pcs You are looking at Z-type foam filters that are compatible with many models of inflatable hot tubs. Please note that you will see many misshapen versions of these filters for roughly the same price, such as square or hexagonal. They are this shape because they are cheaply made and obviously not as well-fitting as the round types which give a more consistent surface. They are also unusually thick, which obviously restricts water flow and puts unnecessary strain on your pump. Why put a thick, hexagonal piece of foam in a housing that is designed for round filters? I used the original filters myself for around 12 months and noticed that they only lasted for around a week. It was almost impossible to clean them. More importantly, they were costing me a fortune. I decided to look at a foam alternative and after around 6 months of trial and error, I settled on the filters you can see in this listing. I have been using them ever since without any problems at all. These are much cheaper than the original filters, much more free-flowing and I find that they filter much better. I have managed to source round filters instead of the cheaper misshapen ones that are sold elsewhere. These will filter water much better due to the consistent surface and have been proven to fit better. These filters require more attention and I recommend using bromine as this chemical is odorless, cheaper, better for your skin and much more filter-friendly. If you choose to use chlorine, I highly recommend changing these filters weekly. Please note that these filters will lose some color when in use. This is perfectly normal and nothing to worry about. Other sellers dye their foam green to hide this, but I believe in being completely transparent with my customers.