1, the contact area is different. Professional jade bracelet calipers adopt included angle structure design, which can ensure that the contact range of calipers is larger and the measurement is more accurate; However, the common ruler has a small contact range and the measurement is not accurate.

2, the scope of application is different. Professional jade bracelet calipers are mainly made of steel, alloy, plastic and other materials, and equipped with suitable readers to meet the measurement needs of objects in different environments and materials; However, the material, structure and measurement accuracy of ordinary rulers are simpler than those of professional jade bracelet calipers, and the scope of application is narrower.