An intriguing piece of retro gadgetry that lets you view the magnetic patterns recorded on tape. A modern day version can be found here: https://store.arnoldmagnetics.com/product/284/magnetic-viewer-b-1022 Special thanks to Andy on Twitter who first made me aware of this device back in 2016 https://twitter.com/andyAVAVsystems/status/786861354594492416?s=20