The C9692 photon detection unit from Hamamatsu Corp. assists low-light-level measurements. The device incorporates a photon-counting photomultiplier and electronics with a power supply and a USB interface. With an active area of 16 X 18 mm2, the detector achieves spectral response of 185 to 650 nm. A built-in shutter is used to adjust integration time from 0.001 to 10 s in steps of 1, 2 and 5. Excitation options include an external laser with the A9859 fiber optical panel or a ring of 375-nm LEDs within the A9860 excitation unit.