Specially designed for collecting sand, silt, gravel, or rock debris carried by streams or immediately above their beds. Ideal for collecting bed load materials which have partial sizes or a density that does not allow great movement above or away from stream bed. 4 lb. (1.8 kg) Hand-held sampler has a 3” x 3” entrance opening and a 3.22 expansion ratio chamber. 250 Micron mesh bag (sold separately) is made of nylon for excellent abrasion resistance. Sampler made of stainless steel. Handle extends from 4’ to 8’.