Our metal cube is compatible with Nikon's E400, E600, E800, and E1000 upright microscopes and the TE200 and TE300 inverted Eclipse microscopes. This cube is not for use in Nikon's Eclipse TE2000 or TI2000 microscopes and should not be confused with the 91020 plastic cube. Chroma can mount this cube with the following Chroma filter sets: 19000, 19001, 19002, 19004, 19012, 39000, 39001, 39002, 39003, 39004, 39005, 39007, 39010, 31021, 49028, 59001, 59004, 59022, 69000, 69002. It is recommended that Chroma installs this cube to ensure proper gluing and alignment. Note: Earlier versions of Diaphot microscopes used our 91000 (18mm) cubes, but many have been converted to be consistent with all later Diaphot models, which use the 91001 cube.