The HANABI Metaphase Spreader has been designed to provide optimized environmental conditions for the preparation of metaphase chromosome spreads. Temperature, humidity and airflow are set and rapidly stabilized so that when chromosomes are dropped and spread on microscope slides, they are dried in a consistent and reproducible manner. Excessive spreading and chromosome overlaps are minimized so giving rise to better yields of analyzable metaphases. The chromosome spreading process for conventional G-banding or FISH analysis of samples derived from blood cells or bone marrow samples is now more streamlined and can be easily carried out regardless of skill level.Some protocols require that cells and chromosomes are spread on the entire slide and this can be achieved using a tilted slide block that is also available.