wrist coaches

I'm not sure what you are referring to. However, if you're referring to a situaiton where a coach wears a device on their wrist with codes then, I know of one school that does it. They call pitches, pitchouts etc. that way. The coach calls a series of numbers and the catcher looks at his wrist to match those numbers up with what they are calling. For example, he might say 33-3-1-2 and have it be a curve. It is supposed to prevent you from breaking their signals. However, and just an observation, it'd be a good idea if in this process you also make sure that your catcher doesn't flash that signal once they hear the code in a way that everyone in the ball park won't know the pitch.

We use them for catchers. We created a 5x5 matrix (11..12 ->54..55). Each number has a pitch/location associated with it. We will hand signal in 3 numbers and let our catchers know if we are "front" or "back". Let's say we are "front" and signal in 512. Our catcher will call the pitch that is in location 51.

Collegiate Baseball ran an article on using the Wrist Coaches for offensive purposes. I think Texas does this.

have used it offensively and for pitching...had kids that just couldn't learn signs, and certainly couldn't change them live, so we used a number system. worked well and we had 4 cards each game so we could change if needed. we used a body part to "color" column, then they just had to count and look down. had a friend who coached softball that shouted the numbers out...some were blank spots and meant nothing, he was successful. if i signaled to a kid to "do nothing" he'd do that well I'm sure!!!