Those large round Fort Knox brand padlocks are pretty well bolt cutter proof , there's no room to cut the hasp and the casing is very stout . For a cable or chain to resist a bolt cutter it has have a diameter greater than the average jaw opening size for the cutter most likely to be used , generally 3/8" or larger cable/chain will frustrate most thieves . Thieves are creatures of opportunity by nature , the harder you make it for them to steal the more likely they will be to move on to an easier target .