While unscrewing the injector button head, a second wrench must be used to assure that the injector body is not loosened from the main valve. 在拧松注入器圆头螺栓时，要用第二个扳手固定住注入器，防止其从主阀门上松落下来。
A wrench used for turning large pipes,an adjustable chain circles the pipe with its ends connected to the head whose teeth engage the pipe. 用来旋转大的管道的扳手，一个可以调整的链条其头尾部连在管道头部锯齿合在管上。
