The BD Horizon Brilliant™ Ultraviolet 661 (BUV661) Dye is part of the BD Horizon Brilliant™ Ultraviolet family of dyes. This tandem fluorochrome is comprised of a BUV395 donor with an excitation maximum (Ex Max) of 350-nm and an acceptor dye with an emission maximum (Em Max) at 660-nm. BUV661, driven by BD innovation, is designed to be excited by the ultraviolet laser (355-nm) and detected using an optical filter centered near 660-nm (e.g., 670/25 bandpass filter). The acceptor dye can be excited by the Red (628–640-nm) laser resulting in cross-laser excitation and fluorescence spillover. Please ensure that your instrument’s configurations (lasers and optical filters) are appropriate for this dye.