The Sprague stethoscope is a rugged instrument specially designed to suit most professional requirements. The 640 series features a threaded chest-piece drum that permits the use of 5 interchangeable chest pieces: an adult and pediatric diaphragm, and 3 bells (1-1/4", 1", 3/4"), all included, for accurate detection of high, middle, and low frequency sounds in children and adults. Proscope 640 features 16" tubing and 1-year warranty. Adscope 641 features 22" tubing and 5-year warranty. Black.