Harmony 1 are very flexible. Harmony 2 are more rigid but still flexible and consequently give you a “little more bit.”
Poponcini Harmony Loose Ring with Copper Inserts
This bit comes in either Harmony 1 or Harmony 2 wrapped in copper. The copper wrapping has a two fold effect. First, it makes the bit a little less flexible at the edges. Second, it makes them less prone to chew damage which makes them more durable as well as helps them to salivate more.
Made in Italy