The Micromixer Chip is a glass microfluidic device designed for millisecond mixing of three fluid streams. Fast mixing times are required for the study of reaction kinetics, sample dilution, improving reaction selectivity, rapid crystallisation and nanoparticle synthesis. The chip can be supplied with a chip holder and a chip header to allow quick connection of fluid pipes. The Micromixer Chip is a static mixer (no moving parts), which at low flow rates creates lamination of the flow streams. The lamination of the streams reduces diffusion distances and hence improves mixing time. At high flow rates swirling occurs in the flow streams, reducing mixing time even further.