Angle measurement range:1/4, 1/2, 1, 2, 3, 4, 5, 10, 15, 20, 25, 30 Angle error: plus or minus 20 Precautions for using the gauge:1. Before measuring, the measuring of the gauge and the measured of the part should be cleaned to avoid the presence of dirt that affects the measurement accuracy. It is wrong to use precision measuring tools such as vernier calipers, micrometers and dial indicators to measure forgings and castings, or surfaces with abrasives (such as corundum, etc.), which can easily cause the measuring to wear quickly and lose accuracy. 2. Gauges are measuring tools and should never be used as substitutes for other tools.micrometer in your hand, which can easily cause the gauge to lose its accuracy. 3. During the use of the gauge, do not stack it with tools and knives such as files, hammers, turning tools and drills to avoid damaging the gauge. Do not place it on the machine tool casually to avoid the gauge falling and being damaged due to the vibration of the machine tool. 4. Do not place the gauge near the magnetic field, Color: As Shown Material: steel Package Contents: 12pcs x Degree Precision Ground Angle Block Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.