how to read air fuel ratio

{"title":"52mm Air Fuel Ratio Gauge","imgUrl":"https:\/\/img.chinax.com\/nimg\/b6\/2c\/b1e74d02cf3797c42b7e6001202d-200x200-1.jpg","attrs":{"Price":"Negotiation","Brand Name":"CAMMUS","Model Number":"Liquid crystal gauge","Minimum Order Quantity":"1 piece","Delivery Time":"10work days","Certification":"Other","Place of Origin":"Shenzhen,Guangdong,China","Payment Terms":"L\/C, T\/T, Western Union, MoneyGram","Supply Ability":"1000 Set\/Sets per Month","Packaging Details":"Standard Packaging","Type":"All Parameters","Function":"Shows 13 parameters","Installation":"Plug and Play DIY","Universality":"Universal for All Cars","Category":"OBDII Gauge","Package":"1*Box, 1*Gauge, 1*User manual","Warranty":"2 Years"}}

{"title":"ECM 3408300 M11 Electronic Control Module Engine Spare Parts For Cummins","imgUrl":"https:\/\/img.chinax.com\/nimg\/ae\/23\/4c2475d3d2b8e168faae62e16bab-200x200-1.jpg","attrs":{"Price":"USD500\/pc-USD800\/pc","Brand Name":"Cummins","Model Number":"M11","Minimum Order Quantity":"1 pc","Delivery Time":"3-7 working days","Certification":"CE\/ISO","Place of Origin":"CHN","Payment Terms":"T\/T, Western Union, MoneyGram, L\/C","Supply Ability":"50000 pcs \/month","Packaging Details":"Original packing, Neutral packing","Part Name":"ECM","Part No.":"3408300","Engine Model":"Cummins M11 engine","MOQ":"1 PC","Size":"Standard","Color":"Standard","Weight":"12 kg","Application":"Marine\/Generator set"}}