Compared to other photosensor technologies, such as PiN diodes, APDs, and PMTs, SiPMs offer a winning combination of properties. These include high gain, excellent PDE, and fast timing along with the practical advantages associated with solid-state technology: compactness, ruggedness, low bias voltage, and insensitivity to magnetic fields. Each SiPM series combines high photon detection efficiency (PDE) with low dark count rate; and with other varying characteristics that are suited to specific applications.