The 25 micron size is the best choice for dry sift, bubble or other fine material.
Rosin Evolution bags are known for their quality & features:
Dimensions: 5,08 x 7,62 cm / 2x3" (inches)
Rosin Evolution bags are designed to withstand heat and pressure.Each bag will hold 5-15 gr. and is turned inside out for maximum yield.The 25 micron bag also has a custom seam specially designed to contain fine particles and prevent blowouts.