Omega Optical (Brattleboro, VT) has developed three new filter sets for use with CoralHueTM Keima-Red fluorescent protein. The new filter sets include versions with both longpass and band-pass emission filters to accommodate a variety of single and multi-fluor applications. Developed by researchers at RIKEN and Hokkaido University in Japan, Keima-Red has an extremely large Stokes shift, making it very useful for tracking protein-protein interactions and for multi-fluor use in fluorescence cross-correlation spectroscopy. These features make it possible for researchers to excite two labels with a single laser for simultaneous fluorescence, resulting in the ability to track protein localization in cells, as well as for monitoring gene expression. The spectral curves of Keima-Red and its optimized filter sets are available online in Omega’s Curvomatic, an interactive database containing fluorescent probes and filter spectral data.