Urrr... I guess I lost my touch
The person who makes it doesn't want it.
The person who buys it doesn't use it.
The person who uses it doesn't sees it.
The person who sees it used should never see it again.
What is it?
Oh, and,
if it takes 8 men 12 days to dig a whole with a spade each, each taking 12 hours resting time each day, how long will it take 2 men to dig half a hole each resting 9 hours each day?