A custom word can be specified, which will always be used in the searches. Very useful to find webpages around a certain topic. Leave blank or as '*custom word*' to disable. You can specify extra parameters such as site and filetype restrictions in this field, as described in Google's reference documentation.
The number of words used in the search can be 1 to 5. Using more words will find more obscure websites, but also increases the chances of not finding anything.
Selecting safemode will filter all adult material from the searches. This is
a filter provided by Google, and while no filter is 100% effective, it is very
good at removing any questionable content.