i've been using the stainless steel full cheek with copper rollers in the link below, and i was wondering if anyone could help me further understand the purpose of it. I know the copper encourages salivation and for the horse to accept the bit, but i was wondering about the structure and how that affects my horse and the severity of it. thank you!!

Metalab Pessoa Stainless Steel Full Cheek Bit with Copper Rollers Mouth