The revolutionary FAST Wireless Air/Fuel Meter Kits allow enthusiasts to monitor air/fuel ratios and data log directly from any smart phone. Features & Benefits: • Monitor air/fuel ratio directly from any iOS or Android smart phone • Pause and review up to 120 seconds of previous air/fuel ratios and rpm • A selectable relay output can be used as an RPM window switch, lean A/F safety cut-off or vehicle immobilizing anti-theft feature • Supports all popular fuel types including Di