Yah, I have quite a few Neodymium magnets from experiments i've done... the biggest I have is 2"x2" circular one like that.... and when I got them in(5 years ago) I had them sitting 3 feet apart on the table and I picked one up got a little too close to one and it pulled my hand right to another one, and BAM, I've got 2 fingers in between them, #$*#&@$*(@#&$**(!!! You can probably guess what I yelled out, yelling, and swearing... lol Took two other ppl and two giant screw drivers to get my fingers out, soo strong. It felt like they were going to fall off, literally!
Anyways those hold, IIRC, 350lbs... so my fingers had 350lbs of pressure on them.
That thing must be a half ton magnet, at least...
That's where I got my magnets from too, I recognize the picture.