Spring

From Speedsolving.com Wiki

The spring is a piece of most twisty puzzles, generally located inside each center piece with a screw going through its hole. Springs are known to be very fun to play with, but are generally not advised to be eaten as they are choking hazards and not digestable. Springs (hardware) are not to be confused with the season Spring, in which many WCA competitions and records have been set.

See Also