Ah I see. Those are the wellDisc.Sitting on top of the wellfloat, directly below the feet of the preamp. What gives them away is the little hole.
information from the website:
Stainless steel plates with special coating (WELL COATING) on both sides. Very robust giving better grip. Long lasting performance for humid environment. These plates can be used on or underneath a WELLFLOAT board to improve grip for better performance of products such as the feet of HiFi devices or spike shoes/pads.