These chrome-plated German steel chains are guaranteed not to break, tarnish or rust. If you have one that did, then it wasn't a Herm Sprenger.

How do I measure my dog for a choke chain?
Measure around the largest part of your dog's head, then add 2 inches. Select the chain size that is equal to or larger than this measurement. Chain sizes are based on overall length from the end-of-the-ring to end-of-the-ring. Length is approximate to within 1/2 inch.