可调式螺纹环规校准是美国特有的AGD螺纹环规校准的方式，采用set plug 来进行校准，而set plug又有多种形式，期待您的咨询。 http://www.gsgage.com.cn

Thread Ring Styles. Solid Thread Rings – The ISO standard used to set the zero systems variable ITC units. AGD Thread Rings – Comply with ASME/ANSI B47.1 gage blank standard. Sizes below 1/4 (M6) are counterbored to hold a specific length. Southern Style Rings – Set and stays round through all adjustments ..