The set consists of 5 floor skirting boards from the manufacturer BelloDeco. The models are splines with the Sweep modifier. To get the plinth you need, just copy this modifier and add it to your spline. All models are named according to the manufacturer's part numbers.
The BelloDeco company produces skirting boards, cornices, moldings, platbands from impact-resistant material - XPSpolymer. The entire range can be viewed on the website: www.bellodeco.ru.