The ProxKey III is a proximity keyfob offering HID proximity technology in a convenient, pocket size device. It easily attaches to a key ring, badge clip or lanyard. This Fob is built to withstand harsh operating environments or handling and is suited for use in access control applications where a Photo ID is not required. Key Features: Small enough to fit on a key ring. Universal compatibility with HID proximity readers. Offers universal compatibility with all HID proximity readers. Provides an external number for easy identification and control Can be placed on a key ring for convenient entry. Supports formats up to 85 bits, with over 137 billion codes. Lifetime warranty