These or the WEEB* lugs are about the only reliable way of grounding a solar panel in many cases. The often used method of using a self-tapping screw to attach a wire fails more often than not due to the copper-aluminum corrosion.
UL listed.
*The WEEB grounding system uses a different
approach, and is probably better, but there have been several reports of electrical inspectors rejecting that method. We
sell the WEEB components for IronRidge and Direct Power rail mounts.
This, or something similar, is required in the NEC code. For more information on panel grounding, see these links:
PV
Systems--Should They Be Grounded?
Home Power Magazine article on PV system grounds