Sex Panther - 90u - Cold Cure Live Rosin (Swamp Water Fumez x GMO) What is 90 Micron mean? 90-micron live bubble hash is a high-quality cannabis concentrate made using an ice water extraction process. The "90-micron" designation refers to the size of the mesh screen used to filter the trichomes from the plant material during the extraction. This size (90u) is known for capturing a balanced mix of resin heads, often considered one of the most desirable grades due to its purity and potency.