The image shows a round knob with a glass surface and grooved design. The bottom is black, and a USB cable leads from it. The knob is likely used for volume control.

This product is compatible with (for example):

The image shows a yellow testing device with two large metal plates in the center. It has buttons and symbols, including "OK" and warning signs, for checking the grounding.
PGT 120 personnel grounding tester for
access control, ++special version++
incl. power supply unit and footwear electrode
Footwear electrode
++ Special version with an RS232 interface to connect e.g. to time recording terminals, test results are provided via RS232 interface ++

832,00 EUR

This product is similar to:

The image shows a yellow testing device with two large metal plates in the center. It has buttons and symbols, including "OK" and warning signs, for checking the grounding.
PGT 120 personnel grounding tester for
access control, ++special version++
incl. power supply unit and footwear electrode
Footwear electrode
++ Special version with an RS232 interface to connect e.g. to time recording terminals, test results are provided via RS232 interface ++

832,00 EUR