3M™ Futuro™ Comfort Lift™ Knee Support, Large, 1 Box of 3 Penlights Parts for 790 Knee Walker: Bell Horn 18mmHg AntiEm Parts for 790 Knee Walker: Caster Threaded chestpiece drum of chrome plated zinc permits the use of five interchangeable chestpiece fittings an adult and pediatric diaphragm and three bells (11 4 1 3 4 ) for complete diagnostic capability in most patients * Latex free double tube configuration * Proprietary valve mechanism eliminates acoustic leakage * Adjustable chrome plated brass binaurals * Complete with an accessory pouch containing the bell chestpieces chestpiece key 2 spare diaphragms one pair of mushroom eartips and one pair of silicon eartips * Inspected and packaged in the U Four way stretch and contoured design conforms to your knee for comfort and mild support Large size is for knees 17 to 19½ inches in circumference