Hello Radsafers, Does anyone know of or have any experience with very high volume air samplers which allow the use of 47-mm air samples (2-in. diameter filter head)? I am not interested in using 4-in. filter heads. If so, please respond directly to me. Vendor names and phone numbers would be most helpful. Thanks! Michelle Doty mailto:Michelle_D_Doty@ccmail.rl.gov 509/373-6788