Big Blue Water Purifiers 1.PP Filter 2.The prodact are have liability insurance 3.Micron Rating (Nominal): 5 Micron 4.Filter Media: Polypropylen 5.Replaced every 3-6 months depends on water quality 6.Change when color darkens or water flow slows Big Blue Water Purifiers Model No.:Big Blue-1 Big Blue Water Purifiers Type:1stage 1stage:Pre-filter 5 Micron PP filter