This filter cube is new "old stock" from a former Nikon dealer inventory. It will fit the Nikon Eclipse series of fluorescent microscopes, E400, E600, E800 and TE200/300. It is in the catalog with a product number of 96178. The list price is $585.00.  The cube is in new condition and still in its' plastic bubble case.. Nikon lists this filter in its' catalog as: Green Fluorescent Protein at 480nm long pass HQ 485 LP.