What are they?
These are insoles that have magnets embedded in them allegedly so that a magnetic field can be applied to the body. This allegedly has healing properties. Some of the claims for this are suggested to be due to magnets improving blood supply.
Do magnetic insoles work?
No they don’t. Every single study that has been done on them shows that they do not work. They are a scam and there is no mechanism by which the could work. The magnetic field in the magnets used in therapy devices are too weak to affect blood flow. They are no better than snake oil.