What is the difference between a calf turn-out-halter and a colt halter?

I really don't want to buy and return back to co-op time and time again. I did find a calf rope halter, but since Ruby2's head is so small I would have to cut the excess rope off so make if safe for her to wear out in the field. Don't need her to learn at an early age how to pop a halter...LOL