The ABB OVRT240-660C is a surge suppressor replacement cartridge, part of the OVR range of surge protection devices. It is the field-replaceable element that fits into the base unit of a compatible OVR series surge arrester, meaning when the protection element degrades or takes a hit, you swap this cartridge rather than the whole assembly.
For BOM planning, this means the cartridge is a stable line item — no imminent obsolescence risk.