· Ideal for businesses that are labor-intensive or have high employee turnover· Operates on 56 business-exclusive frequencies and features 121 codes for added security· Rechargeable lithium ion battery provides up to 18 hours of battery life. Choice of rechargeable lithium ion or backup AAA, with accessory.· Transmits up to 200,000 square feet, or up to 15 floors in a multi-level building· Key pad lock prevents accidental changes to the settings