6204 TN9/C4 Deep Groove Ball Bear.

Open deep groove ball bearings have a very wide range of applications and are the most common bearing type used in, for example, electric motors. The deep groove ball bearing has a simple structure, is suitable for high rotational speeds, and requires little maintenance. These features, along with an affordable price, make deep groove ball bearings the most widely used rolling bearings. Deep groove ball bearings are available in both sealed (permanently lubricated) and open designs. They are also available in stainless steel (W-prefix marking).

Common suffix markings:
- C2, C3, C4 = clearance class (normal clearance without marking, C1-C2 clearance less than normal, C3-C5 clearance greater than normal).
- TN9, M, ML = cage material (steel cage without marking, TN9 = nylon, M = brass).
- Z, 2Z = metal shield on one side/both sides.
- RSL, RSH, RS1, 2RSL, 2RSH, 2RS1 = rubber seal on one side/both sides.