A Flat swivel has both plates parallel to each other. The distance between both plates is the same at all four edges. To determine, hold and observe the swivel at eye level while twisting your wrist to see all four sides.

This swivel has a plastic race. The race is that white plastic sandwiched between the two plates. You can see 4 tabs on it. Each tab contains a ball bearing keeping it separate it from the next bearing for even distribution.

Obviously, this is a Tilted swivel. The two plates are not parallel to each other. The Tilt amount is 3 degrees, an industry standard for chair comfort.

This particular swivel has a "full race". One more bearing cannot be squeezed in. There are no empty spaces between bearings as in a swivel having a Nylon race as shown on photo top right.

A full race swivel is used whenever there is heavy use or heavy loads as it will hold up longer and is Commercial.