As wintton says about the D ring have it brass or another metal that will be rust resistant and can take wear, i have one of them collars where the metal is dipped in some shyney meltal coat that has flaked off with little wear has started to rust. Also use strong thread where the stiching is so over time with wear and tear it doesn't start to come un-stiched. How about a soft material or leather under neath so it is a comfy fit and won't rub on the dogs skin. And keep it looking as simply and plain as possible were looking at the dog not the collar