If you don't have the budget enough to buy an ESD "gun", you can make it by yourself, exclusively in order to verify the quality of your Printed Circuits.

Interesting photos on the details of the ESD discharge

Taking advantage of the availability of the Eng. of CE Laboratory, I wanted to verify the physical protection realized with the “tips” of discharge (spark gap) that generally I use in the development of the printed circuits of the plans with lightning risk (lighting) or unexpected overloads (surge).
The SINCLAIR Phone Dialer has been realized with these tips on the PCB intended as upstream protection of the classic primary and secondary protections.
This is a demonstration of a ESD discharge test