As a result of my tests, I determined that these magnets are incredibly strong and durable, making them perfect for industrial use. They come in a large pack, so you'll have enough to last you a long time. However, the magnets are quite small, so they may not work for larger jobs.
Don't buy it unless you want to use the amount of heat required for a 3mm post on a 2mm post. Firing pin is bullshit. The only way I've gotten them to work is by sanding down all of the firing pin tips. Another step and a huge waste of time. Don't worry and avoid disappointment.