And High Quality Color: Blue Qty: 4 pcs You are looking at Z type foam filters that are compatible with many models of inflatable hot tubs. Please be aware that there are many poorly shaped versions of these filters available at similar prices, such as square or hexagonal designs. These shapes are often the result of low-quality manufacturing and do not fit as well as round filters, which provide a more consistent surface area. Some of these alternatives are also unusually thick, which can restrict water flow and place unnecessary strain on your pump. The original filters I used lasted only about a week and were difficult to clean. After extensive testing, I developed the filters offered in this listing. I have been using them successfully with no issues. These filters are more afable than the originals, allow better water flow, and provide improved filtration performance. I have sourced round filters instead of the inferior misshapen alternatives commonly found elsewhere. The consistent surface area ensures better filtration and a proper fit. These filters require regular maintenance. The use of Bromine is recommended, as it is odorless, gentle on skin, and compatible with foam filtration systems. If using Chlorine, it is strongly advised to replace the filters weekly. Please note that these filters may fade slightly with use. This is normal and does not affect performance. Some sellers dye their foam green to mask discoloration, but I believe in full transparency with customers.