F99 is fingerprint RFID controller; S99 is RFID controller, no fingerprint; Choose it carefully mounting Base is optional F99this is Mini Metal Case Standalone RFID/Fingerprint Access Control with Embedded Design. Support Fingerprint and 125KHz EM Cards. It is an ideal choice to install on door frame. IP66 Waterproof is very sitable for outdoor use. It support Master card and Master fingerprint for easy opeation. Feature: > Embedded Design with Mini size > Metal case and IP66 Waterproof > User capacity:800 Fingerprint and 3000 Cards > One programmable relay operation > Latch mode to hold door and gate open > Tri-colour LED status display Product Name Mini Metal IP66 Waterproof Fingerprint Standalone Controller support 800 Finger and 3000 Cards User Capacity 800 Fingerprints and 3000 Cards Operating Voltage DC9~24V Idle Current 25mA Active Current 100 Proximity Card Reader EM Radio Technology 125KHz Proximity Card Read Range 50px Wiring Connections Relay Output, Exit Button Relay One (NO, NC, Common) Adjustable Relay Output Time o-99 seconds (5 seconds default) Lock Output Load 2 Amp Maximum Environment Meets lP66 Operating Temperature -25~60 (-13°F ~140°F) Operating Humidity 20%RH-98%RH Physical Zinc-alloy plate Colour Silver Dimensions L115xW40xH30mm S99this is Mini Metal Case Standalone RFID Access Control with Embedded Design. Support 125KHz EM Cards. It is an ideal choice to install on door frame. IP66 Waterproof is very sitable for outdoor use. It support Master card for easy opeation.