distance collars to discourage hearding

I use an electronic collar on my dog for sheep herding. It has a button that you can use that just makes a buzzing sound with no electrical stimulation. Maybe that would work for you. It's a Tritronics Sport Basic G3. It works really well, but they're rather expensive. I think I paid a couple hundred for mine. But I use it a lot. Maybe somebody else has some less expensive ideas?!

price is not really an issue for me I just want the behavior to stop before it gets dangerous. I tried using a collar that would beep when he tried to heard, but he really didn't care at all, he was just so into it.

What about a chain in a nylon bag,( I have a barkbusters one) toss it on the ground nearby him to redirect his attention? Onyx is always trying to herd as well, and this does interrupt her, .

A noise distraction would be a great idea but there are a few issues with tossing a chain in a nylon bad. Since I work at a doggy-day care I am around 30 or 40 dogs a day in a room together, this is where vlad does his herding. We have some dogs that are very possive of objects so throwing something isin't always a possibility. I have looked up remotes that emit an ultra-sonic tone that only dogs can hear, but I can not find one that has a recivier collar to where vlad would be the only dog to hear it, or at least he would hear it to the fullest extent and the other dogs would not hear it as loudly. Has any of you found a noise distraction remote with a receiver collar?