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All arm-sizes can be fitted with a Knockstop ®. Both U-shape bent, strips can be firmly attached together on both ends, using  two tie wraps or four nylon blind rivets 3/16" . The correct position for fastening the strips is attained when the middle of the overlapping region is near the inner side of the elbow. See the figures below. Choose the correct size by measuring the elbow circumference/diameter.          
For more safety preferably two holders must be used.

Use a long tie wrap in a rubber hose to secure each holder to the elbow.

Putting on the Knockstop® is easily  and quickly done by extending the tie wrap and then inserting the arm:

Knockstop®: The friendly prevention of aggression. Article: Violence in the nursing home Article: When aggression follows dementia
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