Answers.Body: <p>That is 4 separate parts. They can be disassembled, but they are somewhat fragile. The ends are part <a href="https://rebrickable.com/parts/6644/technic-flex-cable-end-ball-connection-with-cage/" rel="noreferrer">6644 Technic Flex Cable End - Ball Connection with Cage</a>:</p>
  <p><a href="https://i.sstatic.net/EtkFI.png" rel="noreferrer"><img src="https://i.sstatic.net/EtkFI.png" alt="6644" /></a></p>
  <p>The middle section is made up of a length <a href="https://rebrickable.com/parts/75c08/hose-rigid-3mm-d-8l-64cm/" rel="noreferrer">rigid hose</a> with a <a href="https://rebrickable.com/parts/flex08c05l/technic-flex-cable-5l/" rel="noreferrer">flex cable</a> inside.</p>
  <p>Rigid hose:</p>
  <p><a href="https://i.sstatic.net/fin5E.png" rel="noreferrer"><img src="https://i.sstatic.net/fin5E.png" alt="rigid hose" /></a></p>
  <p>Flex cable:</p>
  <p><a href="https://i.sstatic.net/9bwqM.png" rel="noreferrer"><img src="https://i.sstatic.net/9bwqM.png" alt="flex cable" /></a></p>
  <p>The cable end includes a hinged door that allows flex system hose to be freely inserted or removed while the door is open. Once the door is in the closed position, the hose is locked in place. Here's what the part looks like with the door open:</p>
  <p><a href="https://i.sstatic.net/L1Jbw.png" rel="noreferrer"><img src="https://i.sstatic.net/L1Jbw.png" alt="6644 open" /></a></p>
  <p>If you're curious why you might want such a piece, it can be used to transfer translational motion down an irregular path. Here's and example from set 8412:</p>
  <p><a href="https://i.sstatic.net/OxRaB.png" rel="noreferrer"><img src="https://i.sstatic.net/OxRaB.png" alt="8412" /></a></p>
  <p>The part is first used to connect the flex system to the control stick inside the helicopter cockpit:</p>
  <p><a href="https://i.sstatic.net/HN6UQ.jpg" rel="noreferrer"><img src="https://i.sstatic.net/HN6UQ.jpg" alt="steps 10 and 11" /></a></p>
  <p><a href="https://i.sstatic.net/n60Zp.jpg" rel="noreferrer"><img src="https://i.sstatic.net/n60Zp.jpg" alt="step 12" /></a></p>
  <p>It's then used to connect one of the cables to the main rotor to provide pitch and roll control:</p>
  <p><a href="https://i.sstatic.net/JKmrb.jpg" rel="noreferrer"><img src="https://i.sstatic.net/JKmrb.jpg" alt="step 21" /></a></p>
  <p><a href="https://i.sstatic.net/g9dod.jpg" rel="noreferrer"><img src="https://i.sstatic.net/g9dod.jpg" alt="example of control" /></a></p>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2021-11-22T17:03:27.873Z
Answers.Text: So it's basically the brake/shifter cables on a bicycle then?  Neat.
Answers.UserDisplayName: Darrel Hoffman
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2021-11-22T18:25:29.500Z
Answers.Text: @DarrelHoffman Exactly! It's very similar to those cables.
Answers.UserDisplayName: jncraton
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2021-11-22T20:52:20.530Z
Answers.Text: Can you really (non-destructively) *dis*assemble these pieces? I always thought they were rather permanent once that door locks closed...
Answers.UserDisplayName: KRyan
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2021-11-22T21:24:32.107Z
Answers.Text: @KRyan You can. I store mine fully disassembled, and I don't recall ever breaking one. They do feel very fragile, though.
Answers.UserDisplayName: jncraton
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2021-11-21T18:39:58.137Z
Answers.LastActivityDate: 2021-11-21T23:00:11.537Z
Answers.LastEditDate: 2021-11-21T23:00:11.537Z
Answers.UserDisplayName: jncraton
Body: <p>This part is made up of three pieces - two identical ball socket ends that fit the standard tow ball size, and a thin rod connecting the two that is freely rotating. This allows the two ends to rotate independently of each other. The visible section of the rod is three studs long, and each end is two studs long, making the whole assembly seven studs long. The pieces do not appear to be designed to be disassembled by the user, hence my assumption that it is a single part.</p>
  <p><a href="https://i.sstatic.net/7wlW7.jpg" rel="noreferrer"><img src="https://i.sstatic.net/7wlW7.jpg" alt="whole assembly" /></a>
  <a href="https://i.sstatic.net/kKwxH.jpg" rel="noreferrer"><img src="https://i.sstatic.net/kKwxH.jpg" alt="close up on ball socket" /></a></p>
  
Tags: <part-identification><technic>
Title: Identify an unusual double-ended ball socket link part
UserDisplayName: Dylan
ThreadText: # Identify an unusual double-ended ball socket link part
  
  (Asked by: username_0 on 2021-11-21)
  
  This part is made up of three pieces - two identical ball socket ends that fit the standard tow ball size, and a thin rod connecting the two that is freely rotating. This allows the two ends to rotate independently of each other. The visible section of the rod is three studs long, and each end is two studs long, making the whole assembly seven studs long. The pieces do not appear to be designed to be disassembled by the user, hence my assumption that it is a single part.
  
  [![whole assembly](https://i.sstatic.net/7wlW7.jpg)](https://i.sstatic.net/7wlW7.jpg)
  [![close up on ball socket](https://i.sstatic.net/kKwxH.jpg)](https://i.sstatic.net/kKwxH.jpg)
  
  **Tags:** part-identification, technic
  
  ---
  
  ## 1 answers
  
  ### Answer by username_1 on 2021-11-21. Score: 15 | Accepted answer
  
  That is 4 separate parts. They can be disassembled, but they are somewhat fragile. The ends are part [6644 Technic Flex Cable End - Ball Connection with Cage](https://rebrickable.com/parts/6644/technic-flex-cable-end-ball-connection-with-cage/):
  
  [![6644](https://i.sstatic.net/EtkFI.png)](https://i.sstatic.net/EtkFI.png)
  
  The middle section is made up of a length [rigid hose](https://rebrickable.com/parts/75c08/hose-rigid-3mm-d-8l-64cm/) with a [flex cable](https://rebrickable.com/parts/flex08c05l/technic-flex-cable-5l/) inside.
  
  Rigid hose:
  
  [![rigid hose](https://i.sstatic.net/fin5E.png)](https://i.sstatic.net/fin5E.png)
  
  Flex cable:
  
  [![flex cable](https://i.sstatic.net/9bwqM.png)](https://i.sstatic.net/9bwqM.png)
  
  The cable end includes a hinged door that allows flex system hose to be freely inserted or removed while the door is open. Once the door is in the closed position, the hose is locked in place. Here's what the part looks like with the door open:
  
  [![6644 open](https://i.sstatic.net/L1Jbw.png)](https://i.sstatic.net/L1Jbw.png)
  
  If you're curious why you might want such a piece, it can be used to transfer translational motion down an irregular path. Here's and example from set 8412:
  
  [![8412](https://i.sstatic.net/OxRaB.png)](https://i.sstatic.net/OxRaB.png)
  
  The part is first used to connect the flex system to the control stick inside the helicopter cockpit:
  
  [![steps 10 and 11](https://i.sstatic.net/HN6UQ.jpg)](https://i.sstatic.net/HN6UQ.jpg)
  
  [![step 12](https://i.sstatic.net/n60Zp.jpg)](https://i.sstatic.net/n60Zp.jpg)
  
  It's then used to connect one of the cables to the main rotor to provide pitch and roll control:
  
  [![step 21](https://i.sstatic.net/JKmrb.jpg)](https://i.sstatic.net/JKmrb.jpg)
  
  [![example of control](https://i.sstatic.net/g9dod.jpg)](https://i.sstatic.net/g9dod.jpg)
  
  > **Comments:**
  > **username_2**: So it's basically the brake/shifter cables on a bicycle then?  Neat.  
  > **username_1**: @DarrelHoffman Exactly! It's very similar to those cables.  
  > **username_3**: Can you really (non-destructively) *dis*assemble these pieces? I always thought they were rather permanent once that door locks closed...  
  > **username_1**: @KRyan You can. I store mine fully disassembled, and I don't recall ever breaking one. They do feel very fragile, though.  
  
  ---
  
  