Features: 24 high airflows cotton pad (2mm thick) designed for optimal gas exchange in mushroom cultivation, maintaining ideal humidity while promoting healthy mycelium growth in monotub setups. Each 2.95 inch adhesive disc features backing for easy installation, eliminating the need for poly film or micropore tape, and fits standard 2.5 inch monotub air holes with universally compatibility across Myco series and DIYer tubs. Ideal for home mycologists, commercial growers, and DIYer enthusiasts seeking efficient monotub ventilation solution for mushroom substrate maintenance. Use these filter discs in monotub cultivation systems to create a contamination resistant environment during colonization and fruiting stage of gourmets or medicinal mushrooms. Crafted from breathable cotton materials, these reusable filters withstand humid conditions while ensuring consistent airflows—a must have upgrade for reliabled mushroom cultivation supplies. Specifications: Component:Cotton Diameter:Approx.7.5cm/2.95inch Package Includes: 24PCS Reusable Filter Discs note: 1.Please allow 1-2cm errors due to manual measurement, make sure that you donot mind befores you order. 2.Due to the differences between different monitors, the picture may not reflect the actual color. Thanks for your understandings.