mFluor™ UV375 Maleimide is an excellent building block that can be readily used for labeling biomolecules that have a free thiol (SH) group such as antibodies and thiol-modified oligos. mFluor™ UV375 (MFUV375) dyes have fluorescence excitation and emission maxima of ~355 nm and ~375 nm respectively. These spectral characteristics make them an excellent alternative to BD Biosciences' BUV395. mFluor™ UV375 dyes are well excited by UV laser of 355 nm with emission centered around 375 nm, which perfectly matches the filter set of 379/28 nm used for BUV 395. In contrast to polymer-based BUV 395 dye, MFUV375 is a small organic molecule that can be readily conjugated to antibodies. It is dimmer than BUV395, might be used for brighter markers (such as CD4). AAT Bioquest's mFluor™ dyes are developed for multicolor flow cytometry-focused applications. These dyes have large Stokes Shifts, and can be well excited by the laser lines of flow cytometers (e.g., 355 nm, 405 nm, 488 nm and 633 nm).