Sensitive acoustics combined with a comfortable lightweight design make the Cardio Dual head an excellent value. Features include an ultra-sensitive random fiber diaphragm, chrome plated zinc alloy and brass chest piece, Extra Thick Walled Tubing with an inside alloy sound conductor for increased sound transmission. Advanced styling includes an inside binaural spring, chrome plated brass binaurals and color matched soft ear tips for the best in comfort and performance. Lifetime Limited Warranty.