Related Clues:

• That's a job for the letter
• Work for 21 across
• Perhaps where to stick the 20 down
• Stick to your job
• The sort of job that's only for the lettered
• Job in mail
• That may be winning letters - just the job!
• By the sound of it, let 'er work with this
• 'Dispatch (4,3)'
• 'Job for a male, by the sound of it (4)'
• Button on email programs
• Pack (off)
• With 13-down, it's placed in the upper right corner of an envelope
• Email button
• Sergeant's station