Bit from Trust Equestrian.

Trust bits are handmade and made of sweet iron, which has a sweet taste and stimulates saliva production. The bits will lose their blue color over time and become rust-colored.
Be careful to dry the bits thoroughly after riding.

A curb gag bit is similar to a regular gag but has a different effect. The pressure is not applied behind the ears but on the lower jaw. The rope goes under the chin, and the jaw parts are attached to the extra ring on top.

This bit is effective for strong, hot horses and is most often used in jumping.