Standard Tau2 as well as legacy Photon cameras both have one moving part – the shutter. The mean time between failure, or MTBF, is driven by the shutter. MTBF for the legacy Photon camera is 108,501 hours or 12.4 yrs (for a continuous or 100% duty cycle at an ambient temperature of 23 °C). The MTBF for Tau2 with a shutter is similar. The MTBF for Tau2 without a shutter is estimated at 14.8 years, using the legacy Photon as a baseline.