Viavolt 820W LED, dimming, High Bay Grow Light. 27.8'' x 12.5'' x 4.5", with Inventronics LED driver. The Viavolt high bay LED grow light offers a true LED Efficacy: 2.5μmol/J, and true 1:1 HID HPS replacement. this powerful and versatile commercial LED grow light comes with dimming option and is wired 120-277V. The measuring Compact design: 27.8'' x 12.5'' x 4.5"