When in the CW Mode we often use some special characters or a combination of characters that have a specific meaning in "CW". 2 of those combination of characters is "AR" and "SK".
AR is sent meaning, "I am through sending".
SK is sent usually at the very end of your CW conversation or QSO.
Hamsphere has "shortcut" keys for each of these characters.
To send "AR" simply press the "+" key.
To send "SK" simply press the "@" key.