This is the 2009th most frequent Russian word.
устройств
The word "устройств" is the genitive plural form of "устройство," which means "devices," "systems," or "arrangements" (depending on context).
The word 'устройств' is here used in the Genitive plural to indicate possession of or type of items, specifically electronic devices.
Я купил несколько новых электронных устройств.
I bought several new electronic devices.
In this sentence, 'устройств' is used to specify the type of items needing experience for maintenance, expressed in the Genitive plural form.
Обслуживание таких сложных устройств требует опыта.
Maintaining such complex devices requires experience.
Here, 'устройств' designates the variety of items available for purchase and is used in the Genitive plural to describe the selection.