The combination bolt lock? When we first saw this we were we were puzzled! and went away. Then we thought about it and went back. Simple, genius. Its Not Cheap, but cheaper than a Yale or Mortice lock to supply & fit, and can be fitted to doors that cannot take those type of locks. Despite what the manufactures say, this lock is best for keeping "honest people out". I doubt it would withstand a sledgehammer, crowbar or chainsaw, but it is as strong as the door and the fixings it is fitted too. The more you think about this lock, the greater its uses. To keep people out of areas that are unsafe, private, confidential, etc. People who know the combination can get access, those who don't, cannot! Its is ideal for office use, youth clubs, social groups, child care providers, etc. And you dont need lots of keys!
Have a think on this one, and you may come to the same conclusions as us.