If you often think "Did I lock the door?" after you leave home, this app can be a help for your feeling of uncertainty!

Here is how it works:
- it is very simple "Lock the door then Tap the app"-

For example, fifteen minutes after you leave the house, if you start to think "Did I lock the door?". Rather than run back home to check, simply look at your "Lock Checker" app.

The check history you made in the app when you locked the door confirms it's done. If there is no check-history, you better go back. "Lock Checker" just saved your day from disaster!

No need to check or re-check from today. No worries at all!