Ready-to-use suspension of 0.5 µm polystyrene micro beads that can be excited by a blue light source. It is recommemded to be used as a small size reference standard for laser alignment of flow cytometers equipped with a 488 blue laser. This suspension serves as a reference standard for positioning regions after specific configuration installations like CyStain BacCount Total or Viable on the CyFlow Cube 6 V2m.