This kit was the follow up release to Greyscale Gorilla HDRI Light Kit Pro and includes around 50 HDRI studio images that can be used to light a scene, plus an HDR studio rig and seamless floor.
This is more of a drag-and-drop lighting kit than Light KIt Pro. You add the studio rig to your scene, choose an HDRI, drop in the seamless floor, then tweak the scene to taste.
A good set of HDRI images can make a difference when lighting and this set is certainly useful. You can add an HDRI and set up a floor manually in Cinema 4D, but this set accelerates the process, looks professional and saves time. Definitely worth having, especially if you pick it up in the value bundle Greyscale Gorilla offers.