The serial number of Kobold products can be found on the type plate, usually located on the rear or bottom housing of the product.
This location is applicable to:
VK (135, 136, 140, 150 and 200)
EB (350,351,360,370 and 400)
HD (35,36,40,50 and 60)
VR (100,200 and 300)
All other Kobold products have the type plate located at a different place than described above:
SP (520 and 530). It is located on the rear housing of the arm.
PL 515. Located in the lower housing (remove bristle plate for access)
VG 100. Located in the lower housing (remove mop for access)
PB (420, 430 and 440). Serial number under the connector with the hose.
VB 100. Located inside (remove filter bag for access)
VC 100. Located on the inner chassis (remove filter housing)