The 25 micron size is the best choice for dry sift, bubble or other fine material. It can also be used for flower if you are looking for very clean oil.
Rosin Evolution bags are known for their quality & features:
Dimensions: 7,62 x 15,24 cm (3x6" inches)
Rosin Evolution bags are designed to withstand heat and pressure.Each bag will hold 25-50 gr. and is turned inside out for maximum yield.For best results, aim for 1000-1500psi and limit each bag to 40g of material.The 25 micron bag also has a custom seam specially designed to contain fine particles and prevent blowouts.