Articulated fingers are available on Moving Sex Dolls (upgrade) and Ultra-Realistic Sex Dolls (standard feature) only at this time.

Standard doll finger joints are made from wires.  Unfortunately these wires tend to break quite easily after repeated bending of the fingers.  Articulated finger joints are made of stainless steel and are much more durable.  See comparison of standard fingers and articulated fingers.

 

The articulated finger bones mimic real fingers with joints for a more textured and realistic representation of the hand.  For those who take pleasure in photographing dolls, the upgraded finger joints allow for fine-tuning of details, especially when posing, and the flexibility of the bending angle of the fingers adds to the realism of the doll.

In addition, the upgraded finger bones can support lighter objects such as plastic water bottles, thanks to their stainless steel material that can bear a little weight. The normal finger bone can only be used to hold very light items such as pens.
 
The articulated finger bones have a “cap” on each finger to prevent the fingertips from piercing the TPE skin, that is a great way, but they can also pierce the fingertips in the same way as common fingers made of hoses in case of improper protection or violent impact.  However, Its advantage at this time is that if the articulated finger breaks at the joint, it can largely be recovered by tightening the screw.