Answers.Body: <p>This is a <a href="http://alpha.bricklink.com/pages/clone/catalogitem.page?P=7049b#T=S&amp;O=%7B%22ii%22:1%7D" rel="noreferrer">7049b - Wheel brick</a>. It was used with the first LEGO wheels back in the 60's to create vehicles like this:</p>
  
  <p><a href="https://i.sstatic.net/cmeYe.jpg" rel="noreferrer"><img src="https://i.sstatic.net/cmeYe.jpg" alt="enter image description here"></a><a href="https://i.sstatic.net/qvSFf.jpg" rel="noreferrer"><img src="https://i.sstatic.net/qvSFf.jpg" alt="enter image description here"></a></p>
  
  <p>This was a very common piece (in white and black) when it was produced between 1959-1992 and was used <a href="http://www.bricklink.com/catalogItemIn.asp?P=7049b&amp;in=S" rel="noreferrer">in 176 sets according to BrickLink</a>.</p>
  
  <p>Per @GalacticCowboy's comment: As shown in the inset, the wheels had a metallic axle that snapped into the holes. Because they were modular, you could use wheels in whatever configuration you desired.</p>
  
Answers.ContentLicense: CC BY-SA 3.0
Answers.CreationDate: 2015-10-19T16:13:47.377Z
Answers.LastActivityDate: 2015-10-20T12:59:56.660Z
Answers.LastEditDate: 2015-10-20T12:59:56.660Z
Answers.UserDisplayName: Phil B.
Body: <p>In an old plastic bag with heterogeneous Lego bricks, I found three or four like this.
  <img src="https://i.sstatic.net/cvUHZ.jpg" alt="A strange brick"></p>
  
  <p>I can't recognise them: does anybody know what they are? In which set(s) were they used? What for?</p>
  
  <p>A few more details. The small red tubes sound like they are slightly loose inside the brick. The one that connects the long sides is unobstructed (while of course it interrupts the other two).<br>
  From above, the brick looks like normal 2×4 black one, apart for the holes on the sides:
  <img src="https://i.sstatic.net/arXUQ.jpg" alt="The strange brick from above"></p>
  
Tags: <part-identification>
Title: What is this black brick with red tubes inside?
UserDisplayName: DaG
ThreadText: # What is this black brick with red tubes inside?
  
  (Asked by: username_0 on 2015-10-19)
  
  In an old plastic bag with heterogeneous Lego bricks, I found three or four like this.
  ![A strange brick](https://i.sstatic.net/cvUHZ.jpg)
  
  I can't recognise them: does anybody know what they are? In which set(s) were they used? What for?
  
  A few more details. The small red tubes sound like they are slightly loose inside the brick. The one that connects the long sides is unobstructed (while of course it interrupts the other two).  
  From above, the brick looks like normal 2×4 black one, apart for the holes on the sides:
  ![The strange brick from above](https://i.sstatic.net/arXUQ.jpg)
  
  **Tags:** part-identification
  
  ---
  
  ## 1 answers
  
  ### Answer by username_1 on 2015-10-19. Score: 15 | Accepted answer
  
  This is a [7049b - Wheel brick](http://alpha.bricklink.com/pages/clone/catalogitem.page?P=7049b#T=S&O=%7B%22ii%22:1%7D). It was used with the first LEGO wheels back in the 60's to create vehicles like this:
  
  [![enter image description here](https://i.sstatic.net/cmeYe.jpg)](https://i.sstatic.net/cmeYe.jpg)[![enter image description here](https://i.sstatic.net/qvSFf.jpg)](https://i.sstatic.net/qvSFf.jpg)
  
  This was a very common piece (in white and black) when it was produced between 1959-1992 and was used [in 176 sets according to BrickLink](http://www.bricklink.com/catalogItemIn.asp?P=7049b&in=S).
  
  Per @GalacticCowboy's comment: As shown in the inset, the wheels had a metallic axle that snapped into the holes. Because they were modular, you could use wheels in whatever configuration you desired.
  
  
  ---
  
  