Counting chamber is used for microscopically examining water. Can also be used for dust examination, and can be hermetically sealed and employed in the growth of micro-organisms. Made up of a glass slide 33 x 70 mm with a 20 x 50 mm chamber 1 mm deep. Made entirely of glass, with the cover supports inlaid in the base. Supplied with cover glass. Cover glass is optically flat on both sides and 0.5 mm thick.