The high open area minimizes stagnant water to cut sampling time in low-yield wells. The Ultra-Fine filter pack can reduce turbidity by orders of magnitude. This prepack is designed to fit inside Geoprobe® 3.75" Probe Rod. 2" ID x 2.8" OD x 0.25" Slot Size  (20% open area) SpecificationsOuter Mesh: 65 mesh stainless steel screenSand Pack: Ultra fine (US Silica size 00n)Inner Mesh: 120 mesh stainless steel screenPVC Screen: 2" sch40 x 5' x 0.25" slot size (20% open area) Overall Dimensions: 2" ID x 2.8" OD x 5' Length