There are three types of Jump Rings.
1, Jump Rings
2, Pendant Jump Rings
3, Double Jump Rings
Used as a joint between the Chain and Wheel/ Hook or Eagle.
Pendant Jump Rings:
Basically goes with K18 Gold Sun Metals/ K18 Gold in Sun Metal/ Grass (L)/ Metal with Stamp (Ex: Rose, Eagle etc…)
Double Jump Rings:
Used as a joint of the Feather and the Chain.
The bottom one would be sightly smaller than Pendant Jump Rings.
We do hope it helps you to see what you exactly need!