This is a TRW MCC550-4 clutch set.

TRW is a major, trusted brand in automotive parts.
This specific set includes 4 clutch plates (or discs).

The key dimensions are: Outer Diameter (OD) of 125.2 millimeters, Inner Diameter (ID) of 100 mm, and a Thickness of 3 mm.
The overall weight of the set is 0.272 kilograms.
It's crucial to use the part finder or cross-reference with your vehicle's service manual to confirm this set is the exact match for your car's make, model, and engine.

Clutch sets like this are used in manual transmission vehicles to engage and disengage power from the engine to the gearbox.

This is a replacement part designed for professional mechanics or experienced DIYers performing a clutch job.
Ensure you have the correct tooling and knowledge for installation.