Bioelectric prosthesis are what are called hand of robots. It works on a more complex principle than traction, and uses a battery as a power source. Special sensors that are hidden in the forearm, read an electrical signal. The signal is processed and transmits the command for compression - the fingers are compressed. In other words, to take something, you need to strain the muscles of the forearm. Depending on the strength of the muscle tension, the grasp will change: for example, a slight strain of the muscles will signal the fingers to take something "gently", for example, the egg without breaking the shell.
On an example it can be seen here - https://youtu.be/KkDFSqJdZpA
Bionic prosthesis also has its own chip - with its help you can pay in the store. In the prosthesis is built a miniature map - mini-tag, with its help you can pay for purchases in the store or a prosthesis in public transport in one touch. Look at this - https://youtu.be/EZCAIXDhDRY