McKesson Push Button Aluminum Crutches with Wing Nut Hand Adjustments Lighter than wood, the standard aluminum crutch provides stability and durability Double-extruded center tube provides additional strength to weight-bearing area Pushpin adjustment makes it easy-to-adjust crutch height in 1″ increments Non-skid, jumbo-size vinyl contoured tips provide excellent traction Easy wing nut adjustments for hand grips WARNING: This product can expose you to bisphenol A (BPA), which is known to the State of California to cause birth defects or other reproductive harm. For more information, go to http://www.P65Warnings.ca.gov.