The adjustment of the tightness of the lining of the fiberglass safety helmet is mainly achieved through straps and adjustment devices. There are two common adjustment methods: knob type and pull-out type. For rotary adjustment devices, there is usually a knob on the back or side of the safety helmet. The user first wears the safety helmet on their head and adjusts its position so that the hood can fully cover the top and sides of their head. Then, adjust the tightness of the hat lining by rotating the knob. When turning the knob clockwise, it will tighten the strap of the hat lining, making the hat lining fit more tightly to the head; Turning the knob counterclockwise will loosen the strap, increase the space between the hat lining and the head, and make the wearing more relaxed.

Pull type adjustment devices are generally equipped with pull straps at the rear or on both sides of the cap lining. After wearing the safety helmet, find the drawstring and pull it outward to tighten the helmet lining and better secure it to the head; Push the drawstring inward or loosen it to loosen the hat lining and adjust it to the appropriate level of tightness. During the adjustment process, it is important to pay attention to moderate elasticity. If it is too tight, it may cause discomfort to the head, and wearing it for a long time may cause headaches; If it is too loose, the safety helmet is prone to displacement when impacted and cannot effectively protect the head. Generally speaking, it is more appropriate to adjust the gap between the helmet lining and the head by about one finger, which can ensure the stable wearing of the safety helmet and provide a certain degree of comfort.