You can customize certain aspects of Threshold to your liking. The methods for doing this are described below.
The Preferences Dialog
The Preferences dialog contains several customizable options.
 
Autoswitch battery warning options
Threshold has the ability to switch between different warning sets, depending on whether an internal or external battery is attached. Through the preferences dialog, you select which sets you want to be used. The popup menus allow you to select one set to be used when an internal battery is attached, and you can select another set for use when an external battery is attached.
Sleep button
This option allows you to bypass the "Putting the computer to sleep may cause you to lose some network services" dialog. When the box is checked, hitting the "sleep" button will put your PowerBook to sleep, even if AppleTalk is enabled. When the box is unchecked, you will get the warning dialog if you try to put your PowerBook to sleep with AppleTalk enabled.
The Customize "Warnings" menu dialog
 
When you first start using Threshold, sets 2 through 4 are labeled "custom". This isn't very descriptive, but through this dialog box you can relabel them to something more meaningful to you. For example, if you have both an internal and external battery, you might want to label set #2 "internal", for use with your internal battery, and set #3 "external", for use with your external battery. Note that Set #1 is always the Apple default warnings, and cannot be changed.
Altering the warning thresholds
By using the arrows on the bottom of Threshold's window, you can alter when the warnings will occur. If you move the warning threshold up, the warnings will come earlier. If you move the warning thresholds down, the warnings will come later (when your battery is lower). Note that the arrows adjust the current warning set, so check the "Warnings" menu first to determine the current set. Also note that you cannot alter the default Apple warnings.
Threshold automatically limits how far you can vary the warnings. The highest voltage that Threshold will allow is 6.20v, and the lowest voltage depends on your model of PowerBook, and whether your copy is registered (if it is registered, the voltage can be dropped even lower).
Regardless of which warning set you are currently using, when you quit Threshold it will restore the warning thresholds to the Apple defaults.