Manufactured by Princeton Instruments, the ProEM professional-grade electron-multiplying (EM) CCD cameras are suitable for use in low-light applications in single-molecule fluorescence, astronomy and ion imaging. The 512 × 512 and 1024 × 1024 back-illuminated EMCCDs support both electron-multiplying and traditional readout ports. Features include a Gigabit Ethernet interface, a Bias Active Stability Engine and on-demand gain calibration that produces a linearized gain map. The all-metal-seal vacuum design provides deep cooling and low dark current. The cameras can be cooled with air, liquid or a combination of the two.