Home / Standards / GBT 39645-2020 GBT 39645-2020 Technical drawings — Proportions and dimensions of geometrical tolerance symbols 技术制图 几何公差符号的比例和尺寸 Standard Type GBT ICS N/A CCS N/A Status N/A Issue Date N/A Implementation N/A Responsible Dept N/A Drafting Unit N/A