Anti-Rotation Adapter

  • Anti-Rotation Adapter for Ø1/2" Posts
  • Imperial and Metric Compatible


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  • Maintain Rotational Alignment of a Post
  • Attaches to Imperial or Metric Ø1/2" TR Posts
  • Tongue of Adapter Aligns to Groove in Post Holder

The TRK05 is an adapter for TR series posts that prevents the post from rotating during a height adjustment when the post is held in any PH or UPH series post holder. The adapter attaches to the bottom of a TR series post using the included low-profile 1/4"-20 or M6 cap screw. A key on the TRK05 fits precisely into the machined channel in the PH and UPH series post holders. A TR post outfitted with the TRK05 adapter is shown to the right as the post is aligned and inserted in to the post holder. These adapters are particularly useful when swapping post mounted components to decrease the alignment time. Use with an R2 (R2/M) collar and maintain the post height adjustment for even quicker component swapping.

Thorlabs also offers slip-on Ø1/2" post collars. These collars offer an alternative option for customers looking to restrict post height as well as rotational orientation.

Posted Comments:
楚鹏 张  (posted 2023-06-15 11:16:06.217)
jpolaris  (posted 2023-07-03 12:12:16.0)
Thank you for contacting Thorlabs. We have attempted to reach out to you but have not heard back. Please feel free to contact your local technical support team at
tcohen  (posted 2012-04-19 15:00:00.0)
Response from Tim at Thorlabs: Thank you for your feedback! We are glad to hear you enjoy and find use for our design!
user  (posted 2012-04-19 12:09:13.0)
Excellent idea & implementation. Great value (think of the time you'd spend realigning that optic if you didn't have this tool).
tcohen  (posted 2012-02-24 17:08:00.0)
Response from Tim at Thorlabs: Thank you for your feedback. Because of the fit and the fact that the notch in the post holder that determines its fixed rotation is opposite to the spring loaded thumbscrew, the stability of the post should not be affected.
user  (posted 2012-02-23 01:26:09.0)
These seem like a good idea but do these adaptors interfere with the stability of the post if they are not perfectly centered? Also, I think your price is just fine, unlike that other poster....Yes, in America we are free to make a profit from innovation...other countries don't allow this...seriously do not let these cheap skates make you feel guilty about what you charge. If they like it and need it then they have to PAY for it. If they think it is too expensive then don't buy it !!! But then you have to live with out this great American innovation so pay up or shut up...Now I think you should double your price and see what they say...
bdada  (posted 2012-01-30 11:42:00.0)
Response from Buki at Thorlabs: Thank you for sharing your thoughts with us regarding the TRK05 anti rotation alignment key. We agree with your assessment and are working on a redesign that would be less expensive. We would like to send you a sample of the prototype when it is ready. As a temporary solution, we would like to send you samples of the current TRK05. Regarding our product philosophy here at Thorlabs, we strive to help our customers be as efficient as possible and that includes providing the best pricing and design for our products. In cases like this where we have not provided the best possible solution, your feedback is invaluable in getting us to rethink the product. Thank you again for your feedback.
ben.jian  (posted 2012-01-28 00:48:06.0)
This product is quite useful but too expensive. I need 9 units of it but the cost stopped me. I would reduce the cost of it by stamping the profile out of cheap sheet metal. Can you offer this greatly reduced part? What's the product philosophy at Thorlabs - do you strive to provide products that lower customer's cost or to maximize Thorlabs' profit?
Based on your currency / country selection, your order will ship from Newton, New Jersey  
+1 Qty Docs Part Number - Universal Price Available
TRK05 Support Documentation
TRK05Anti-Rotation Alignment Key for TR Series Posts