More than 100 different immunoassays using those references show very good analytical performance (excellent signal/noise ratio, good precision, low CV, excellent linearity and reproducibility) when used in the most common immuno-analyzers. The use of magnetic beads in Immunoassays, Cell Biology, Quantitative Lateral Flow, Biosensor or Biochip technologies are becoming very common. Several sophisticated systems are under development and the immunoassays are more complex. In order to meet the changing needs of our customers, we started an R&D program to significantly reduce the size of our Superparamagnetic Microspheres. In a first step, we reached 300nm, and then 200nm and finally we succeeded with very small beads of 150nm! They offer a great surface area and increase the sensitivity, a very low sedimentation rate, high ferrite content and a good magnetic signature. Our very small beads are used in various biological applications such as cell sorting, immunoprecipitation and of course, quantitative lateral flow assays.