Equipment code "z"

[MickJ26]

I'm going through the Dubai past performances and there's a few horses with a lowercase "z" in the equipment column. I'm unfamiliar with this one and Googling it hasn't shed any light. Anybody know? Thanks.

[ArlJim78]

z is a tongue tie.
http://www.equibase.com/newfan/page5-1.cfm

[MickJ26]

Much obliged Jim, sir.
I don't recall ever seeing it before.
I thought all horses raced with them?

[chadk66]

why on earth would they tell you whether or not a horse wears a tongue tie. the number of horses wearing them is staggering.