From the Manufacturer https://www.ekwb.com/shop/ek-uni-rad-holder-120   EK-UNI RAD Holder 120 provides various placements of radiator outside PC cases or any other surfaces suitable for mounting your favorite radiators.  This way users are allowed to take PC tuning one step further.  Holders come packed in a pair of two with mounting screws.  Made of steel (black painted).