jonny b.
Please find another way to secure the chain. I was a firefighter for 10 years…if, heaven forbid, anything should ever happen and your babies need to be rescued, a firefighter isn't going to have bolt cutters in his or her hand and won't have time to search for a combination. We carry a radio, flashlight, charged hose line and an axe into a fire. If it's just the dogs working their way loose, just hang the lock on the chain but don't latch it.
Yes, firefighters do try to rescue pets from fires. I've rescued cats, dogs, fish, birds and a turtle. We even have special muzzle oxygen masks on the ambulance.