**Requires amplifier or connector cord depending on phone make/model. The Plantronics EncorePro 500 headset series is an all-new generation of headsets for customer service centers and offices, designed for the future, and built on experience. Three innovative models deliver greater comfort for all-day wearing, superior noise-canceling for clearer calls, and increased reliability so conversations can continue without worry. And theyâ€™ll help you meet the OSHA / Noise at Work regulations. Complete flexibility means high-performance for every work-style. The all-new Plantronics EncorePro 540 is a quantum leap in convertible headset design. Itâ€™s a 3-in-1 headset without compromise â€“ all of the wearing styles are designed with quality and comfort in mind,in a system that is simple to convert but delivers a secure, positive fit and finish. The HW540 shares the advances of the other members of the new family, with high-quality audio, a flexible mic with visual positioning guides, soft ear cushions, and durable-yet-lightweight materials for all-day wearing.