Rosin Evolution bags are designed to withstand heat and pressure from a Rosin press (1000-1500psi recommended). The 25 and 37 micron bags also have an extra fold in the seam to better contain fine particles. We have 160, 90, 37 and 25 micron rosin bags in stock at amazon.com/shops/rosinevolution. Other bag sizes, volume discounts and custom options also available!