These polyester rosin bags are ideal for use with the Rosinbomb, but are universal so can be used with other presses. They have a 250 micron gauge so they are perfect for pressing flower or other herbal materials and giving you the maximum yield. They measure 4.5 inches by 2.5 inches and can hold up to around 14 grams of material for each pressing. Available in a pack of 10 or 25, please see drop down.