Enter how many passwords you would like, or leave blank for ten. I recommend generating 25 of between 8 and 12 characters. Keep in mind that passwords with 6 characters have a possible 308,915,776 combinations whereas 8 characters increases the possible combinations to 208,827,064,576. Furthermore, passwords generated here will have far less combinations due to the limitations on being pronounceable.
To prevent abuse, the number of characters is limited to 64 and the number of generated passwords is limited to 1000. Because it takes you longer to read one password than it does to generate them, there is no need to load the server down with 1000, 64-character passwords.