Whatman 6722-5000 VACU-GUARD Vacuum Protection Filter, 50mm Disc (Pack of 10) 50mm disc Helps to confine and isolate infectious materials in vacuum systems and protect your lab Designed for in-line use with stepped barb connections for 10-12mm ID hose Hydrophobic PTFE membrane retains 99.99% of airbone particles greater than 0.1m Ideal for protecting vacuum pump systems