The Quick Scaler is a function of the Tower Glove that allows you to quickly scale items in your Condo up and down. It has been made mostly obsolete due to the Gizmos' scale function.
To use the Quick Scaler, left click an item with it equipped to scale it up slightly (.05x by default), and right click to scale it down. The max you can scale an item up to is 10x, and the max you can scale it down is to 0.1x. By pressing R and left clicking on an item, you can reset its scale back to 1x.
You can press C to open the tool settings menu, which allows you to change the Quick Scaler's scale factor (.01 to .10), or set a specific scale (0.1 - 10) to set items to when shot.