Already compatible with the accessories designed for the previous arms. Some I already included within this page, these are also available
Smartphone holder: 

[https://makerworld.com/it/models/2519027-smartphone-tablet-holder-for-the-modular-arms](https://makerworld.com/it/models/2519027-smartphone-tablet-holder-for-the-modular-arms) 

Swivel clamps/base:

[https://makerworld.com/it/models/2519055-swivel-rotating-clamps-base-for-the-modular-arms](https://makerworld.com/it/models/2519055-swivel-rotating-clamps-base-for-the-modular-arms) 

Helping hands adapter:

[https://makerworld.com/it/models/2551408-helping-hands-adapters-for-modular-articulated-arm](https://makerworld.com/it/models/2551408-helping-hands-adapters-for-modular-articulated-arm) 

This articulated arm is redesigned from the ground up to solve the main weakness of my two previous 'versions': while the resistance to forces applied to the arm rotation axis has always been great, strong forces perpendicular to it could make the hinges give in more than I liked.

The twist-lock improved on that but not enough. This new mechanism has two sets of 'teeth' offset from eachother, one to lock the rotation, and one to lock the two hinges in that position; in order to separate they would have to break.

The only drawback is the absence of a "retention" mechanism during adjustments, the arms/hinges are free to move when the rotation isn't locked so they need to be held together manually until it is. 
But, that also makes it extremely easy to rearrange, there's no locking tabs and it's more durable.

Perks don't end there though, with this new mechanism all you need to make it work is something to push the button/inner piece, I personally recommend 10x3mm magnets but it can also work with springs, even 3D printed ones, making it possible to assemble without any external hardware.

Assembly steps:

• A complete hinge is made of the A and B counterparts, the inner piece, and whatever you want to use to push it. Use magnets together with 'Magnet Holder'.
• 'A' and 'B' hinges alternate: the clamps/base are A --- B arm/hinge goes on them --- then A and so on.
• There's a 'male' and 'female' connector. The accessories (headphone holder, smartphone holder, etc) and the swivel clamps/base have a female connector, use a hinge with a male one to connect to them.

Extra tip for magnet orientation: imho the easiest way to make sure the magnets push against eachother is as follows: put a magnet into the 'inner piece' (I suggest using the 'magnet tool', just makes life easier). Lay the second magnet on the opposite side, flat on the button (it will be held in place by the one already inside the piece). Take the magnet holder and push it on the magnet.

The .step files for hinges, connectors and arms are already included. If you need one specifically feel free to ask.