The most used hands are the Phoenix hands which exist in several variations with dental elastics or wire elastics.
The most used arm is the Unlimbited arm
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The Phoenix hand is elegant, on the other hand the force on the dental elastics cannot be finely adjusted, they must be replaced often, are not necessarily easily found everywhere, and do not withstand intensive use or climatic conditions.
If your recipient has a very small palm and little strength, prefer the Phoenix reloaded which allows very fine adjustment of the elastic tension.
Dental elastics tend to break. To use in difficult environments such as hot countries, prefer cord elastics, which are much more resistant.