The lamp shade adopts Pyrex with good light penetration and less penetration loss. 玻璃罩材料为耐热玻璃，透光性能好，透射损失小。
In the environment with lower noise level, the earplug will decrease its sound insulation factor accordingly to ensure the useful voice can be heard. 在低声级环境中，其隔音量又足够低，可以保证能接收到一些有用的声信号。
