you need to understand one thing if you are looking for cheap solution, even if these go bad in 2~3 months and not perform well for 6 months you are still saving money. I bought these keeping in mind that they will only work for 2~3 months then i will simply replace with other saving money if I buy from authorized local dealer (original ones). Guess what, even after 6 months they are working great though I use them as first round of filtration for my new Kent machine now