SleepTight 1.0.1 for Mac could be downloaded from the developer's website when we last checked. We cannot confirm if there is a free download of this app available.
According to the results of the Google Safe Browsing check, the developer's site is safe. Despite this, we recommend checking the downloaded files with any free antivirus software. The software belongs to Security Tools. This free software for Mac OS X was originally created by Raging Menace.
From the developer:
SleepTight provides a simple way to lock your machine when it goes to sleep or with a keyboard hotkey. Screensaver preferences are automatically modified at sleep to enable the screensaver password prompt even if it has been turned off in the Screen Effects system preferences.
You may want to check out more Mac applications, such as PasswordVault Lite, which might be similar to SleepTight.