STRONG magnets! I was initially worried abut the design and if the magnets would come apart leaving the shoes basically "untied", but these things are strong and haven't come apart at all.
These things work better than expected. I have a bad habit of tying my shoes on the looser side then slipping them on and off as I come in and our of the house. That would case my shoes trauma and leave me with shoes not as secure as they should be for more active things I do. These are perfect, nice snug fit and easy to pop on and off.
Having hurt my hand several years ago I find it necessary to have help tying my shoes because I often do not have the dexterity to do it myself. That being said this product has gave me more independence as I can easily put my shoes on and push the magnets together. They do not slip and stay very snug. I would recommend this product to anyone child and adult.