Instead of tines, Grover's instrument uses a hollow metal tube.

格罗弗的仪器没有使用金属尖片，而是换成了中空的金属管。

And if an electrical current happens to be moving over a hollow metal container, like a can or a box or even a welded coat of armor, the current won't reach the inside of the container.

如果电流恰好流过一个中空的金属容器，比如一个罐子、 盒子甚至一套盔甲，电流并不会触及容器内部。