Part #3899 is often known as Mug.
We know this part is available in LEGO Digital Designer, LDraw, Brickset, Bricklink, Rebrickable and Mecabricks.
You can buy it on Amazon or Bricklink.
Steve and John did their job every day, yet they never stopped to consider that their tools might be too small for the task. After all: everything is cool when you're part of a team.
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