She doesn't like the non-metal kind! I was initially worried about it too, but she won't play fetch without there being a clicky noise when they hit the floor, and I've never seen her chew the metal bit, just the chewy plastic parts. and tbh the elastics last so long that by the time I'm worried about swallow-sized bits I've thrown them away. She has a secret stash somewhere tho, I find them in weird places.