Review on TACKFORM Magnetic Phone Holder V.2.0 with N52 Magnets - Stick On Dash Mount for Car, Kitchen, Bedroom, Bathroom - Authentic 3M Sticky Adhesive - Compatible with Phones, Tablets, GPS Units by Leonard Herrera

They hold my phone very well. I hung one on my car's dashboard and the other on my bedside table. It's been in my car for months and has been exposed to adverse weather conditions as well as 100 degree days with the scorching sun meaning it's been over 100 degrees in my car and it's still holding up great. The only small problem is that the swivel head doesn't want to stay in place in high heat. It still holds the phone great, I just can't position it exactly how I'd like it. After cooling down it works again. The magnets are strong. I didn't want to stick it on the outside of my phone case so it would sit inside my rubber case and still hold up nicely. It's never fallen into a car (and I drive over 100 miles a day, so it's tested well), but it's fallen off my bedside table a few times from hitting it.