VECTASHIELD®HardSet™ Mounting Medium prevents rapid photobleaching of fluorescent proteins and dyes. After approximately 15 minutes at room temperature, the mounting medium will harden, the coverslip will become immobilized, and optimal antifade ability and refractive index of 1.46 will be achieved. Mounted slides should be stored at 4 degrees C, protected from light. VECTASHIELD HardSet Mounting Medium is compatible with a wide array of fluorochromes, enzymatic substrates, and fluorescent proteins. The refractive index is 1.45. This formulation of VECTASHIELD HardSet Mounting Medium contains TRITC-phalloidin. Fluorescent derivatives of phalloidin are used to stain actin filaments. TRITC (tetramethylrhodamine) is excited at 544 nm and emits at 572 nm, producing an orange-red fluorescence.