Microarray scanners are widely used in functional biology, cellomics, gene expression and drug discovery research. When buying a microarray scanner, important features to consider are sensitivity, resolution, scan area, rapidity of scan, and ease of use. Microarray Scanners usually have red, green, and blue excitation wavelengths and a wide choice of up to 8 emission filters that enable imaging of an extensive variety of fluorophores (e.g. Cy3, Cy5, FITC, Texas Red). For high volume use, features such as a laser-saver (for programmable on/off according to workflow needs) increase lifespan and reduce instrument maintenance. Depending on the application and funds available, one might choose a microarray scanner system with autofocus that continually adjusts to keep features in focus while scanning, confocal optics that allow for the sensitive detection of low-abundance targets, or automated multi fluorescence scanning that allows multiplexing.