Inclusion Criteria:  (unilateral acquired transradial) amputation residual limb size requirements to fit investigational device componentry at least 6 residual muscle locations available for implantation good compliance with health service (rehabilitation) willing to undergo surgical implantation of IMES Sensor implants experience with myoelectric upper limb prostheses using own myoelectric device approximately 6-8h/day able to provide informed consent and attend the study visits  Exclusion Criteria:  any condition which in the opinion of the investigator poses a risk to health neurological disorder that may prohibit accurate control major injury proximal to the level of amputation neuromuscular disorder nerve transection or palsy that may cause de-innervation of muscles planned for implantation allergy to implanted materials existing active implant