I've not used this version of the same concept, but the 'original' version was a wood head (and later plastic) that you could reset with a flick of the wrist, rather than manually having to reset the ring by hand with each swing.
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"Support the On Plane Swinging Force in Balance"
"we have no friends, we have no enemies, we have only teachers"
Simplicity buffs, see 5-0, 1-L, 2-0 A and B 10-2-B, 4-D, 6B-1D,
6-B-3-0-1, 6-C-1, 6-E-2