> This is how auto belays work. That is super cool! That said, I'm enough of a layman not to be able to connect this explanation to what I saw in the video.

> This is how auto belays work. That is super cool! That said, I'm enough of a layman not to be able to connect this explanation to what I saw in the video. Are you saying because it wasn't moving in "slow motion," we can rule out non-ferrous metals? Or are you saying the alternating movement/stillness of the magnet shows this?