AppLock is a privacy and security app for Android devices that provides a locking system for all your apps, photos, and videos. It allows you to password protect specific applications, emails, and folders on your device without locking down the entire device. You can prevent accidental or unauthorized access to private emails, SMS, files, pictures, videos, music, etc. while leaving the device available for other uses like phone or internet browsing. AppLock has a Constant Protection Mode for maximum security, provides protection for selected media folders on your SD card, and has a memory optimizer, battery scanner, and static antivirus and malware scanner. Additionally, it offers app lock themes online and offline, wallpapers, and power boost to your device.

AppLock is easy to use and provides a nice GUI that displays the list of installed applications on your device. You can pick individual apps from the list view of apps for password protection. In case of a password forgotten, you can submit a request by just one click and get the password from your email only. The app is free to use and does not require any contact with the developer.

Overall, AppLock is a highly recommended app for anyone who wants an additional level of security on their Android device. It is fast, secure, and works with all Android versions and hardware.