Answers.Body: <p>Primo and Mega Bloks are <strong>not</strong> compatible.</p>
  <p>The Primo piece loosely fits on a Mega Blok piece:</p>
  <p><a href="https://i.sstatic.net/TKw7P.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/TKw7P.jpg" alt="Primo and Mega Bloks" /></a></p>
  <p>But the Mega Blok piece does not fit on the Primo stud.</p>
  <p><a href="https://i.sstatic.net/64wtv.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/64wtv.jpg" alt="Primo and Mega Bloks" /></a></p>
  <p>As for the adapters in your second photo, I have seen them many times in used toy collections I've bought; unfortunately, I don't think I've ever seen them new in the package to give you a specific reference on how to buy them. But I've always assumed they were an actual Mega Brands product.</p>
  <p>I have a 2x2 (or 1x1) and 2x4 (or 1x2) in front of me. The smaller says <strong>430</strong> and <strong>© 1988</strong>. The larger says <strong>439</strong> and <strong>PAT PEND</strong> and <strong>© 1988</strong> and (tellingly) <strong>Ritvik</strong>. (<a href="https://en.wikipedia.org/wiki/Kirkbi_AG_v_Ritvik_Holdings_Inc" rel="nofollow noreferrer">Ritvik</a> was the maker of Mega Bloks.)</p>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2022-09-07T14:43:01.067Z
Answers.LastActivityDate: 2022-10-23T18:23:36.347Z
Answers.LastEditDate: 2022-10-23T18:23:36.347Z
Answers.UserDisplayName: RSchulz
Body: <p>Similar to <a href="https://bricks.stackexchange.com/questions/9618/compatibility-of-maxi-sized-mega-bloks">this</a> question I am interested in combining Duplo Lego with Mega Bloks.
  I want to have full compatibility, i.e. being able to put Duplo on top of Mega Bloks, which requires some type of adapter.</p>
  <p>I am looking for BUYABLE adapter pieces (not self-made via 3dprinter or such).</p>
  <p><strong>Does anyone know a source?</strong></p>
  <hr />
  <p>I found that Lego has a (discontinued) system called &quot;Lego Primo&quot; with similar round studs. It does have adapter blocks for Duplo (marked with red rectangle):</p>
  <p><a href="https://i.sstatic.net/OpXdo.png" rel="noreferrer"><img src="https://i.sstatic.net/OpXdo.png" alt="enter image description here" /></a></p>
  <p><strong>Can anyone confirm that these do / do not fit the Mega Bloks studs?</strong></p>
  <p>Although they are discontinued, they can still be bought used. So if they fit it would be an option for me.</p>
  <hr />
  <ol start="2">
  <li>There is an unconventional type of adapter being sold on <a href="https://www.ebay.com/itm/403461040983" rel="noreferrer">Ebay</a> (seems to be just a single offer, used):</li>
  </ol>
  <p><a href="https://i.sstatic.net/KUM1t.png" rel="noreferrer"><img src="https://i.sstatic.net/KUM1t.png" alt="enter image description here" /></a></p>
  <p><strong>Has anyone ever seen these somehwere else? Maybe even in real life?</strong> They do not look 3d-printed, they look injection molded (like Lego and Mega Bloks). So there might be someone producing them (or having produced them) commercially...</p>
  
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2022-09-07T13:21:58.153Z
Comments.Text: I've linked to the eBay item your picture comes from, in order to let others see the whole listing with all images. Note though that the listing explicitly mentions how _"They are extremely hard to find."_ I can easily imagine someone having set up an injection molding line for these parts, and only producing a handful of them before getting hit by C&D letters from both TLG and Mattel - thus limiting the availability of these parts severely.
Comments.UserDisplayName: zovits
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2024-02-19T18:48:17.267Z
Comments.Text: I have several of the second (white) adapter you show in the photo, from my original 1990s Mega Bloks sets. I have the original Ritvik Mega Bloks (the only size now sold) as well as a Ritvik Mega Bloks set that is almost identical to Duplo blocks (sold in the early 90s, mine are marked 1992), with the white adapters made by Ritvik.
Comments.UserDisplayName: Kara
Tags: <clone-brands><compatibility><duplo>
Title: Adapters for Lego Duplo and Mega Bloks
UserDisplayName: Kjara
ThreadText: # Adapters for Lego Duplo and Mega Bloks
  
  (Asked by: username_0 on 2022-09-07)
  
  Similar to [this](https://bricks.stackexchange.com/questions/9618/compatibility-of-maxi-sized-mega-bloks) question I am interested in combining Duplo Lego with Mega Bloks.
  I want to have full compatibility, i.e. being able to put Duplo on top of Mega Bloks, which requires some type of adapter.
  
  I am looking for BUYABLE adapter pieces (not self-made via 3dprinter or such).
  
  **Does anyone know a source?**
  
  ---
  
  I found that Lego has a (discontinued) system called "Lego Primo" with similar round studs. It does have adapter blocks for Duplo (marked with red rectangle):
  
  [![enter image description here](https://i.sstatic.net/OpXdo.png)](https://i.sstatic.net/OpXdo.png)
  
  **Can anyone confirm that these do / do not fit the Mega Bloks studs?**
  
  Although they are discontinued, they can still be bought used. So if they fit it would be an option for me.
  
  ---
  
  2. There is an unconventional type of adapter being sold on [Ebay](https://www.ebay.com/itm/403461040983) (seems to be just a single offer, used):
  
  [![enter image description here](https://i.sstatic.net/KUM1t.png)](https://i.sstatic.net/KUM1t.png)
  
  **Has anyone ever seen these somehwere else? Maybe even in real life?** They do not look 3d-printed, they look injection molded (like Lego and Mega Bloks). So there might be someone producing them (or having produced them) commercially...
  
  **Tags:** clone-brands, compatibility, duplo
  > **Comments:**
  > **username_1**: I've linked to the eBay item your picture comes from, in order to let others see the whole listing with all images. Note though that the listing explicitly mentions how _"They are extremely hard to find."_ I can easily imagine someone having set up an injection molding line for these parts, and only producing a handful of them before getting hit by C&D letters from both TLG and Mattel - thus limiting the availability of these parts severely.  
  > **username_2**: I have several of the second (white) adapter you show in the photo, from my original 1990s Mega Bloks sets. I have the original Ritvik Mega Bloks (the only size now sold) as well as a Ritvik Mega Bloks set that is almost identical to Duplo blocks (sold in the early 90s, mine are marked 1992), with the white adapters made by Ritvik.  
  
  ---
  
  ## 1 answers
  
  ### Answer by username_3 on 2022-09-07. Score: 6
  
  Primo and Mega Bloks are **not** compatible.
  
  The Primo piece loosely fits on a Mega Blok piece:
  
  [![Primo and Mega Bloks](https://i.sstatic.net/TKw7P.jpg)](https://i.sstatic.net/TKw7P.jpg)
  
  But the Mega Blok piece does not fit on the Primo stud.
  
  [![Primo and Mega Bloks](https://i.sstatic.net/64wtv.jpg)](https://i.sstatic.net/64wtv.jpg)
  
  As for the adapters in your second photo, I have seen them many times in used toy collections I've bought; unfortunately, I don't think I've ever seen them new in the package to give you a specific reference on how to buy them. But I've always assumed they were an actual Mega Brands product.
  
  I have a 2x2 (or 1x1) and 2x4 (or 1x2) in front of me. The smaller says **430** and **© 1988**. The larger says **439** and **PAT PEND** and **© 1988** and (tellingly) **Ritvik**. ([Ritvik](https://en.wikipedia.org/wiki/Kirkbi_AG_v_Ritvik_Holdings_Inc) was the maker of Mega Bloks.)
  
  
  ---
  
  