Handle returns the OS-level handle associated with this Spinbox. On Windows this is an HWND of a standard Windows API EDIT class (as provided by Common Controls version 6). Due to various limitations which affect the lifetime of the associated Common Controls version 6 UPDOWN_CLASS window that provides the buttons, there is no way to access it. On GTK+ this is a pointer to a GtkSpinButton. On OS X this is a pointer to a NSView that contains a NSTextField and a NSStepper as subviews.