Lathem proximity RFID Key FOBs attach directly to a Key Chain and are a secure, compact and convenient device for employees to clock-in or clock-out as an alternative to a proximity badge card. Fobs are a beneficial sized addition to any lathem PC50 system or Lx100 door lock and attach directly to your car Key Chain. Pack of 5. Since 1919, lathem' s singular focus has been to manufacture innovative, durable and affordable employee time and attendance systems.