I do not understand all of the huge discussion about something which
cost $25-30 (compare to your invoice for K3S kit...) and which solving
the ESD task forever...;) but ok...
1. The top layer must be dissipative
2. The bottom layer must be conductive
3. Its nice when the top layer is chemical, overheat and cut
4. Mat must be connected to ground thru 1.5M resistor, NOT ditectly in
order to thru body current limitation if an accident!
5. Wristband is connected to mat in normal cases also thru 1.5M
Just few basic hints for all who would not like to just faith to be
"lucky user" when working with boards like K3S kit etc.
More info you can find here in my article:
You can drop me an email if you want to help with buying the
professional grade ESD mat complete set for your safe bench works on K3S
73 - Petr, OK1RP
Laboratory test equipment,
Design and application, Prague