Hmmm, all three have just flat, woven nylon buckle collars. They wear these all the time, and have all of their ID stuff hanging from the. Also, I took a black sharpie marker and wrote our address and phone number in block letters on the collar itself, just incase the ID tags got ripped off for some reason. All three have chips implanted as well...but I'm a fraidy-cat...
When we walk, Zeus gets a Gentle Leader (he's better than a husky at a sled-pull...let me tell you!), Apollo gets a pinch (He doesn't need it usually, but it actually makes people feel better about hiim...bizarre!) and Onyx gets a regular choke chain.