A single photon detection module for the visible range has been introduced by id Quantique SA. The id100-OEM offers state-of-the-art performance in an extremely compact form factor. Packaged in a standard TO-5 header, a 50- or a 20-μm-diameter Geiger-mode avalanche photodiode integrated with fast-quenching electronics is mounted on a thermoelectric cooler. The device can be mounted on a custom-printed circuit board. A fiber-coupled version also is available.