An ESD Coordinator has to know the ESD sensitivity level of the ESD Sensitive (ESDS) electronic devices being handled or processed to ensure the ESD processes that he sets up for his ESD Control Program is functioning as required and is not creating any ESD damage to the ESD sensitive parts.
ESD Association (ESDA) has issued [...]

There are many type of ESD sensitive parts. Some of the most ESD sensitive parts used in the Electronic Industry are:

Radio Frequency components
Disk Drive head (Magneto resistive heads (MR), Giant Magneto resistive heads (GMR))
Complementary Metal Oxide Silicon (CMOS) Integrated Circuits (ICs)
Gallium Arsenide Field Effect transistors (GaAsFETs)
Reticles
Random Access Memory (RAM) [...]