The Knockstop® is a user friendly device that can be mounted on the elbows or knees of an aggressive person. In contrast to fixation the user can still perform all daily activities. The Knockstop ® only prevents hitting movements with extended arms. These (unexpected ) punches are the main cause of serious injuries. This patented innovation uses the surprisingly small force that is sufficient to prevent the elbow joint from completely stretching. The user can only bend his arms to 90 °.This situation is comparable with a person wearing a sling or an arm in plaster) The patient will behave better and he is more amenable to treatment and behavioral interventions. Knockstop ® can reduce the number and severity of incidents. This new holder can be mounted with a lockable strap in stead of a tie wrap. This version is comfortable to wear for the user and easier to apply for the nurses.