Hydro Times 32 Gallon 4 Bag Bubble Extract System Kit for Herbal Ice (FREE PRESSING SCREEN) Made of high quality waterproof nylon material for extra strength and lasting durablility Filtering screens are made of top notch monofilament Each 32 gallon bag is labeled and color coded to corresponding micron rating 1.) 30 micron = yellow 2.) 80 micron = blue 3.) 130 micron = green 4.) 230 micron = red FREE PRESS SCREEN = 25 micron