HI there Janie!
I haven't heard of that type of collar, but I can suggest using a little bit of lavendar oil for calming. Shelby's doctor was using pure lavendar oil ( a little that is rubbed between your fingers and dabbed on the tip of her ears and her forehead) when she was having PT after her LP surgery. It really helped with making her relax...... also something that may help with car-rides..... apply it about 15 minutes before you get in the car.............. AND it makes them smell so good!!!
You can buy pure lavendar ooil at GNC.
Hope that you find something that helps you!