The study is evaluating the performance of prosthesis control system, referred to as Phantom X, in able bodied individuals and individuals with upper limb amputation at the forearm level.

The study will characterize the performance of Phantom X system and associated algorithms in decoding EMG signals for various hand gesture control. The EMG signals will be sensed using a non-invasive multi-electrode array applied to subjects' forearms.

Inclusion Criteria:

1. Individuals 21 years in age and older
2. Individuals with amputation of one or both arms at transradial level (applies to amputees only)
3. Ability to follow study directions
4. Willingness and ability to sign Informed Consent

Exclusion Criteria:

1. Individuals with previously diagnosed muscle pathologies
2. Individuals with impaired muscle function and/or impaired ability to perform normal hand movements (normal participants) or ability to perform normal phantom hand movements (amputees)
3. Individuals with transhumeral or higher amputation of both arms (applies to amputees only)
4. Cognitively impaired to follow study instructions
5. Allergies to skin adhesive materials necessary for cutaneous electrode placement
6. Excessive hair growth on arms and inability to shave off the hair for electrode placement
7. Pregnant woman
8. Arms or residual limbs with insufficient diameter to accommodate the wearing of two cutaneous sensor arrays
9. Injuries, bruises, or open wounds on the arm that needs to be instrumented for the study