Yes, it is "terret" you can thank good old "spellcheck" for that one!!
The check hook is called just that here, but since I have never, nor shall ever, used one, I did not know the correct term for it and had to go look it up!!
It is not called a "water hook" over here, and the turrets are definitely what the rains go through, not turrets!!
I'm sorry, I have no pictures as I have never used this contraption, only ever advised it's use.
Chuck the checkrein and only use it, nice and loose, for the stupid shows that demand it, is my advice.
It has no place in training, anyway, as the horse should be concentrating hard enough on what it is being told to keep it's head out of the grass.
And spellcheck has just turned all my "terrets" into "turrets" AGAIN, so I've wrestled the flipping thing into submission and got it to recognise "turrets"
Whoopee.
So it tried to turn them into "torrents" this time.
ARGH!!!