Sennheiser SD Pro1 ML Premium Wireless Mono Headset

Specification : 

• Frequency response (microphone) - Wideband Mode 150 Hz – 6.8 KHz 
• Narrowband Mode 300 Hz – 3.5 KHz 
• Frequency response (headphones) - Wideband Mode 150 Hz – 6.8 KHz
• Narrowband Mode 300 Hz – 3.5 KHz
• Weight - Headset: 2.3 oz
• Earpad size - ø 1.96 inches 
• Charging time - 0 – 50%: 20 minutes
• 0 – 100%: 1 hour
• Standby time - Up to 100 Hours 
• Range - line of sight 590 ft in typical office building 180 ft 
• Talk time - Wideband Mode Up to 8 hours 
• Narrowband Mode Up to 12 hours 
• Storage temperature - +41 °F to +158 °F 
• Operating temperature - +41 °F to +113 °F 
• Battery Specification - Lithium Polymer (Exchangeable for service - see manual)
• Speaker type - Neodynium Magnet Speaker