My clients love using the curvy "snake" ring stack that is made from a bird mister. I came across one at a yard sale and have bought several on Amazon (see Affiliate link below) because it requires reaching, using both hands, an upright posture, promotes visual attention and is visually stimulating to watch as the rings twirl down. I use rings that have small openings and therefore, require force to push on with individuals who have good motor control and seek deep pressure sensory stimulation. I use very large rings such as the ones shown when the person has decreased eye hand coordination and it needs to be easy to use.
In this situation I turned the activity into a 2 step process so that they have to unscrew the covers and learn that only the open rings go on the stack and the yellow covers go into the bag. This activity meets the needs of people with different skills. Some individuals are great at screwing them together tightly and some are better at unscrewing the covers.
The covers and screwing pieces are made from the abundant thick- It containers I find at work ....
Notice that the ring stack is positioned according to the person's needs (in the video) and you see it on the table, on a chair and on the person's lap.