Putting on and taking off wrist watch is not too hard even without a sophisticated prosthesis. In fact this is a lot easier without artificial arm. I mean, I tried. I know.
Same procedure with prosthetic hand:
The fact that particularly, modern iLimb or Bebionic hands have an at least somewhat deficient precision grip is exacerbated by this particular use case, where force application is multidirectionally challenging for the wrist watch band situation.
So far, we have not seen any repeatably sound, robust and reliable use of a prosthetic "bionic" hand being able to guarantee a successful fast and reliable putting on of a wrist watch band. Also we have not seen any other such video elsewhere. If anything you read and saw all of this here first.
Using a prosthetic device usually benefits from at least a degree of understanding. While a hook appears to be far more straightforward than a "bionic" hand whose fingers are not tip-position coordinated, that does not mean each and every application is straight forward. The simple looks are deceiving, and only the actual user may know the difference. My former boss often said, "the difference makes the difference".
And a better understanding of what device works better usually does not go past us without leaving at least a trace: and so anyone that really understands how speed, geometry and objects interrelate, particularly in the context of multidirectional grip use, will want a fast body powered snug tight grasp device that has a rigid geometry and that usually today is a body powered hook. And for some situations, it is not even enough to just have that device at your disposal. Sometimes you have to look deeper into the issues.
Here is the wrist watch video that is required to explain what there is to say about conventional watch bands. Putting the wrist watch on is fast an easy if only you know how. Depending on what and where you work you most definitely do not want to use your mouth for that. There might be social pressure to not behave too much like a barbarian or the gripper or other parts around your hands may be covered with something that does not belong in your mouth, such as contamination with biohazards.
Maybe I should have said that this is a really fast act.
You may be able to see it, but I should have stated it, too. Ultimately you want to be fast, I tell you. The fastest and most reliable method is stump against chest (videos above). But the counterbearing trick using any solid edge (keyboard in below video, but any table or shelf will work just as well) while wearing a hook is the way to go.
I did also notice that this may be too fast for visual identification of single aspects, so you see, I am even self critical. So I made the below slow motion video, so all of y'all can follow with ease, using the hook to play slowly across each step along the way, with extensive comments below.
Removing wrist band
0:06 hook pincer grip graps band reliably and firmly due to hook inherent reliable precision grip
0:11 pull band out with care, allowing locking rod to disengage with the band's perforation
0:12 locking rod now disengaged with the band's perforation
0:16 What you need to understand: to make the band glide out of the lock with ease, the locking rod must be pushed aside and since the prosthesis is not able to do that at the same time, you need to use some other surface to accomplish this. The band's surface just adjacent to the hole can be conveniently used for that. To get that, the band must be pulled sideways just a tad bit.
0:28 rod tip lands on band surface adjacent to hole due to slightly pulling the wrist band sideways with the hook
0:30-0:35 the band can be used to push the locking rod into an "open" position now
pushing the wrist band open then does not cause the locking rod to engage with a band perforation, thus the wrist band has been efficiently opened and can be pulled or pushed out all the way if necessary; after that I am just playing with the lose band to show its free move in the wrist band lock
Putting on and closing wrist band
1:34 the presence of a computer keyboard edge (or a table or a piece of wood or an upside down coffee cup or a camera case or whatever really) is required to push the locking rod end into the band perforation
1:41 the locking rod is placed against the edge of the keyboard with the wrist band strap pulled up
1:49 gently lowering the band will catch the rod into the perforation of the band and thus lock the wrist band lock
1:52 this is a first variation, just look where it goes in and lock it there, or you can repeat the process to make it tighter
1:57 the locking bar is pushed against the keyboard edge to move its end / tip into the band perforation, this goes until 2:04 or so
See you later alligator, don't forget to practice!
If you are interested in more work related and difficult work applications, comparing body powered and myoelectric arm technology, here is an informative summary [link].