how to use vernier height gauge

{"cid":"91221137","title":"Double Scale Vernier Height Gauge With Fine Adjustment For Measuring","imgUrl":"https:\/\/img.ismap.com\/nimg\/da\/53\/9bcdc473fc5c169b2635d572aae6-200x200-1.jpg","attrs":{"Brand Name":"KM","Model Number":"KM-421-300","Minimum Order Quantity":"","Delivery Time":"Within 15days","Certification":"ISO DIN GB RoHS","Place of Origin":"Shaanxi, China","Payment Terms":"T\/T, L\/C, D\/P, D\/A, Western Union, PayPal, MoneyGram","Supply Ability":"50000pieces\/Month","Packaging Details":"Polyfoam+Paper Box 62*28*14cm\/Piece 4.20kg\/Piece","Warranty":"One Year","Material":"Stainless Steel","Measurement":"Metric","Measurement Object":"Height","Range":"0-300mm","Precision":"0.04mm","Graduation":"0.02mm","Function":"with Fine Adjustment","Package":"Polyfoam+Paper Box","Customized":"Acceptable"}}

{"cid":"91202047","title":"H13 NAK80 S136 718H Durable Cell Phone Case Mold For Commonly Used Models","imgUrl":"https:\/\/img.ismap.com\/nimg\/ce\/58\/17f06a818816a612f7baf8cdaf25-200x200-1.jpg","attrs":{"Price":"Negotiable","Brand Name":"GODE","Model Number":"G2132411","Minimum Order Quantity":"1 Set","Delivery Time":"15-30 Work days","Certification":"ISO9001","Place of Origin":"China","Payment Terms":"L\/C, T\/T, Western Union","Supply Ability":"35 Sets per Month","Packaging Details":"Wooden case","Product material":"Plastic","Mould materia":"P20\/718\/738\/NAK80\/S136\/2738\/2316","Mould hardness":"Upon request","Cavity steel":"H13\/NAK80\/S136\/718H","Product texture":"according to customer request","Mold Runner":"Hot Runner\/ Cold Runner"}}