The stock settings page contains all the configurations for the Ubercart's stock keeping module.

Send email notification when stock level reaches its threshold value
Checking this value will send out a warning email to store admins when a stock level falls behold its threshold.

Notification recipients:
This is the comma separated list of email recipients for the threshold warning message.

Message subject:
This is the subject of the email message sent.

Message text:
This is the body of the email message sent. The input format of the message can be changed by clicking the "Input format" link below.

For both message subject & message text you can use tokens. The description text below the message text field contains a link to a page that explains what tokens you can use.