Pultruded fiberglass rod is the main body of material, about the size than mandril as a whole more than 70%, plug in to play a supportive role in the skeleton.

• 玻璃纤维是拉挤芯棒的主体材料，约占整个芯棒的体积比70%25以上，在芯棒中起到骨架的支撑作用。