A Wartenberg wheel, also called a Wartenberg pinwheel or Wartenberg neurowheel, is a medical device for neurological use. It was designed the wheel to test nerve reactions (sensitivity) as it rolled systematically across the skin. A Wartenberg wheel is generally made of stainless steel with a handle of approximately 18 centimetres (7 in) in length. The wheel, which has evenly spaced radiating sharp pins, rotates as it is rolled across the flesh. A disposable plastic version is available. Because of hygienic concerns, these devices are rarely used for medical purposes any more.