This tool was used to quieten horses when they didn't want to cooperate with a procedure. One of the wooden bars would be placed on each side of the animal's upper lip / muzzle & the bars would be strapped together at their free ends, squeezing the lip. Theoretically the use of a twitch promotes the production of endorphins in the horse's body, making it calmer . Personally I am rather doubtful about this theory and suspect that twitches worked more by providing the alternative distraction of pain.

This example is made of two pieces of stained beech wood, each with twelve grooves turned around their circumference
The pieces are joined at the top by an iron clip with copper washers
They could be held tightly together by the leather strap attached to one of the handles
Some similar twitches are stamped "Rutter's Patent Twitch" - this one is not
This tool is in good condition considering its age.

Dimensions : Each wooden arm is 12¼" (31cm) long
Weight 347g (12¼oz)
Ref : Misc325-rutters