I have been using the K-Works Ersamat for about 8 years on my Thorens TD-166 MkII. The designer, Igor of K-Works, developed it using his VPI 'table with aluminum platter. It acts to block RFI and EMI from reaching the stylus and entering the signal chain.
https://www.ttvjaudio.com/K_Works_Ersamat_p/kwo0000001.htm