round head button bolt

• 圆头螺栓

round head button bolt的用法和样例：

例句

1. 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。