A valuable tool for waste-water treatment plant operators. Less expensive than glass. Settlometer and centrifuge tests for sludge quality are used in analyzing the activated sludge process. Kit contains a two liter polycarbonate jar, a polypropylene paddle, ten 15mL conical polycarbonate centrifuge tubes, polypropylene closures and an instruction booklet & data sheet. The 2 liter jar is lightweight, transparent, highly impact-resistant and has easy-to-read white graduations. The paddle permits agitation of sample without scratching jar. Designed to fit tabletop centrifuges up to 6000 x g, without cushions or adapters, eliminating the danger of broken glass fragments to operator or centrifuge. All kit components are chemically-resistant to "normal" sludge samples (pH range 3 to 10).