According to Cook’s interview with Witkowski, this device contained two counter-rotating cylinders that would be “filled with a substance similar to mercury, violet in color”.
This metallic liquid was codenamed “Xerum 525” and was “stored in a tall, thin thermos, one meter high and encapsulated in lead.”
It is said that the experiments used additional substances, mentioned as Leichtmetall (light metal, in German), “including thorium and beryllium peroxides.”
https://www.ancient-code.com/meet-die-glocke-the-mysterious-nazi-anti-gravity-machine/ 