This bit has a similar effect as a 3-ring bit but it works softer and has less leverage effect. The upper eye is used to attached the bit to the bridle. The bottom eye is for the reins.
Sweet Iron - will rust when in contact with humidity (air). The surface rust tastes sweet and naturally simulates the salvation production. This will cause the hors to salivate more which will encourage the horse to take more contact.
The process of rusting (oxidisation) changes the blue colour of the Trust bit to a brownish - grey. A sweet iron bit will develop an orange-brow rust layer on the mouthpiece if it is temporarily not used. This is easily removed by wiping it off with a damp cloth.