The PROline 650s, utilizing the same award winning S-Logic¿ technology and gold driver as the HFI-700, are at home in the studio, on the road and even in your home theater setup. These are some of our most versatile headphones and the warm sound they produce is good for most any application. PROline accessories include removable cables and speed switch earpads. S-Logic¿ Natural Surround Sound: S-logic¿ uses decentralized driver positioning to utilize the pinna of the ear in the manner it is used in everyday life, reflecting the audio signal off the surface of the outer ear in different directions before entering the auditory canal. This results in a very natural spacious three-dimensional sound. S-Logic¿ is the only headphone system which includes your entire sense of hearing. Safer Listening: Because the S-Logic¿ technology does not aim the auditory signal directly down the ear canal but at the pinna, pressure to the ear drum is decreased by up to 40% (3-4dB) for the same perceived loudness. This significantly reduces the risk of hearing damage and ear fatigue ¿ an absolute must if you spend a lot of time in headphones.ULE technology: The ULE technology was systematically developed by ULTRASONE for users who spend many hours in the headphones. All headphone drivers produce low-frequency magnetic fields. In response, ULTRASONE developed a special MU Metal shielding (ULE technology) to reduce the radiation by up to 98% compared to ordinary headphones. Tech Specs:Closed headphone,S-Logic¿ Surround Sound,Frequency range 10 Hz ¿ 25kHz,Impedance 75 Ohm,SPL 95 dB,Driver 40mm gold-plated,Reduced Magnetic Emissions Standard,ULE Standard,Weight 295g,2 yr warranty, www.ultrasoneusa.com. PROline box contains:,Two detachable cables one coiled and one straight,Straight length 3m (approx. 9') Coiled <3m with gold plated jacks.,6.3mm (1/4) to 3.5mm (1/8th) gold plated adapter included,Spare pair of speed switch earpads,Demo CD,Carrying bag.