These high performance LED bars are full spectrum and include two peak color temperatures; one at 3500K and one at 5000K. Each channel is individually dimmable to six different levels. To boost foliar growth, turn up the 5000K channel and turn down the 3500K channel. To encourage blossoming and fruiting, turn up the 3500K channel and turn down the 3500K channel. For optimal growth and health, we recommend both channels be set identically. Each bar includes a single power supply, a Y-splitter, and two in-line dimmers. The dimmers remember their most recent settting, so these can be connected to timers and will always come on at the same setting as they were previously set to.