Glass cutter

A glass cutter was a tool used by some rogues to by-pass locked windows.

Uses
Glass cutters were a viable option for thieves wishing to ignore the time-consuming task of getting through a locked window.

A diamond-tipped cutting edge attached to an adjustable arm was attached to a suction cup, allowing for circular cuts of various sizes to be made upon a window pane. After making the cut a simple tap would remove the section of window while the suction cup kept the glass from shattering and making a loud noise.