AccuCount Ultra Rainbow Fluorescent Particles are precision microspheres designed for flow cytometry calibration, instrument standardization, and fluorescence intensity verification. With a uniform size of 3.8 ± 0.3 µm and a concentration of 1 × 10⁶ particles/mL, these beads provide reliable fluorescence reference points for accurate instrument alignment and performance assessment. Supplied in a 5 mL volume, they are ideal for cell biology, immunology, and diagnostic research, ensuring consistent, reproducible, and high-quality cytometry results.