Key Features: - 40mm Dynamic Drivers - Closed-Back Design for Less Bleed in Mic - 15 Hz to 20 kHz Frequency Response - Isolates Listener for Clearer Monitoring The Mackie MC-100 headphones offer the audio performance Mackie is known for in a cost-effective, closed-back design that offers a degree of passive isolation for monitoring. The headphones feature custom, high-performance drivers for clear, balanced sound plus an ergonomic headband and earpads for hours of listening