The file 'P3steel 2.x – Silicone Damper For Printbed 3D Printer Model' is (stl) file type, size is 48.8KB.
Cast mold for heatbed damper.
http://scheuten.me/?p=670
Updates:
I recommend this heat resistent 2 component silicone:https://goo.gl/vXQIKZ