Removable 'touwtje door de brievenbus'

If you want your kids to be able to open the door when they are playing outside, you can put a rope though the mailbox for them to pull. If you have a round doorknop like I do, then this isn't really an option. Therefor I created this simple removable handle. It's removable because I don't want it to be on my door all the time. Let's say I don't want to make it very easy for people who are not my kids to come in. When removed only a small piece is left on the doorknop.

I think it should be