Miller Edge Tru Guard Reflective photo cell (UL325) The Miller Edge Tru Guard Reflective monitored and fail-safe photo optic system is a UL Recognized Component that meets the UL 325 requirement. The Tru Guard Reflective consists of an emitter/receiver unit and a reflector with hood. The emitter/receiver is intended to be positioned in such a way that an obstruction in a hazardous area will interrupt the beam of light. An interruption of the beam will signal the operator to stop or stop and reverse motion. This photo cell will be included with every operator beginning October 2024.