Download of 1Piece 3.1.1 for Mac was on 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 actual developer of this free Mac application is Takahiro Fujita. The program lies within System Tools, more precisely General.
From the developer:
1Piece includes various features to improve the usability of your Mac. Window List that displays a list of windows, a feature that switches the Space or the active window by using Hot Corner, a feature that resize and reposition the window and so on.
You may want to check out more Mac applications, such as SubCleaner, DockMenus or MacWise, which might be similar to 1Piece.