I asked reefbreeders, they said this
The Edge Bars are designed primarily to mount directly onto the Meridian using the Edge articulating mounts or our BOT mounts, utilizing the provided bolts on top.
While it's technically possible to suspend them using hanging wires, we generally don't recommend it, as these bolts run along a single axis. Unlike our Meridian or Photon lights which secure on two axes and easily allow tilt adjustments. The Edge Bars' single row of bolts means tilt adjustments using hanging wires would rely primarily on positioning the power cord.
Our 12" and 24" Edge Bars come standard with two bolts on top, as that's sufficient for secure mounting to BOT mounts or a custom T-track system. However, if you prefer using hanging wires, we do offer additional bolts in packs of two or four to accommodate this.