... .4. 3 step multi-frequency 5. Measurement: Distance, circumference, area, fetal weight, fetal heart rate6. OB measurement: BPD, GS, CRL, FL, AD, HC ... :≤2mm, axial≤1mm Body marks: 15 Measurement: Distance, circumference ,area, heart rate, EDD Comment : date , name , sex, age , hospital , annotationCoded-colors ...