The LiTian Company 100% Nylon Food Grade, Durable Reusable and Cleanable 2.5 x 4 inch Squish Bag Filters have been designed to make contaminent free solventless oil using the Rosin tech, which combines both high pressure and heat to Squish out the trichome heads. All of their bags come already inside out for ease of use and to ensure minimal loss of oil to the seams. The smaller 25 and 45 nylon micron mesh bags are the most suited for squishing dry sift, bubble, dry ice, or other very fine material. The 73 micron, 90 and 120 micron bags also have a specially designed seam used to keep fine particles out of your oil and prevent blowouts; they can be used for flower and lower grade types of hash. These are also the best choices for your flower and leftover trim. The 160 and 190 micron screens can be used to squish out the absolute most from your flower or trim. The 190, 220 and 240 micron SquishIt bags are perfect for squishing out oils to be used for edibles, full spectrum oils for topicals and medicinal purposes.