40x40x20mm Super Strong Neodymium Block Magnet, Permanent Magnet, The World's Strongest and Most Powerful Rare Earth Magnets

This is an interesting review because the number of stars for easy to remove and durability are both one. Normally, a one-star review is bad. But in this case, less starts is good news! Easy to remove would mean a weak magnet, and neodymium magnets are not durable. These are facts. The product advertisement on Amazon covers some of these points. But the question should have been "magnetic grip" and that would have been five stars. Complaining about a neodymium magnet being fragile is like saying an eggshell is fragile. It is the way it is. So, first off, you want powerful magnets? Order these. Good price, fast shipping, good product. You will get what you want. But there is more to the story. These are dangerous in even in experienced hands. I am experienced - and still had troubles. This is not the manufacturers or vendors fault. These are powerful magnets, and any difficulties are the responsibility of the user. Don't order these as toys. To avoid disappointment, you should know in advance exactly what you wish to do with these. I did know, and I had difficulties, because these magnets are so strong they are actually annoying!! I did not want multiple powerful magnets because of the need to avoid crashing magnets together which breaks them, creating sharp shards of metal, crushing fingers in the process. I knew I wanted a single magnet, to demonstrate the long distance effects of a powerful magnet. Other websites had what are probably better magnets at a similar price, but nobody could beat Amazon's shipping costs and time. So I bought four of these. They are shipped two to a small box, together, with a small spacer between them. I knew already I wanted these magnets stuck together into one big one. I knew I wanted to put them into a larger piece of metal to make handling easier and safer. When you order two, they come packed in the same box, separated by a piece of plastic and cushioned in styrofoam. Getting a magnet pair separated was difficult, but doable. I knew that bringing two pairs together in a controlled manner would be very difficult. Knowing that these magnets will accelerate towards each other in an instant, I put one pair outside the cardboard they shipped in, placed a magazine inside the box for extra spacing and cushioning, and brought them together. As expected, they flew together. But I could not move them enough to get the magazine out or slide them to the edge of the cardboard. The attractive force was so great the cardboard was compressed to nothing. I ended up cutting around the magnet outline, through the cardboard and the magazine. I decided to put the magnets into a vice, gripping the two lower magnets only. It took 20 minutes to get them properly oriented in the vice. Sliding and twisting the magnets required the use of a crowbar and vice grips. Using the bench vice and large water pump pliers, I was able to get enough separation to slide a wooden shim between them. Using the shim, I was able to get all the paper out between the magnet pairs, then slide the shim out, thus bringing the magnets together in a controlled fashion. This took another hour! I brought the four magnets into the house to tinker. From 18 inches away, a 3" diameter ceramic magnet, with a couple small disc magnets attached, slammed into my new big magnet. All three ceramic magnets broke and chipped my new big magnet. I was pretty confident 18" was enough separation. There is a very nice set of smart phone apps written by Keuwlsoft. Go to the play store, search for Keuwlsoft, scroll down and look for the "Gauss Meter." It is free, but you get ads. They are not bad, but I always buy the apps because I want to reward the creative minds that create these tools. The app turns the magnetometer inside your smartphone into a Gauss meter, allowing you to measure and quantify the intensity of magnetic fields. This Gauss meter picks up my new big magnet from a few feet away. Bringing the phone closer, hits the 45 gauss limit of the meter. It affects compasses and other magnets at a similar distance, which is exactly what I want to demonstrate to my students. 45 Gauss is a lot! The earths magnetic field average 1/2 a Gauss. Since I do not want to ever separate these magnets, I decided to put them into a protective metal sleeve. I used a 3" long piece of 2" x 2" x 1/8th" piece of square tubing. It was my intention to center the magnets in the tube by driving wooden wedges into place. The magnets had other ideas, and simply getting them into the tube required a hydraulic press. Driving a wedge between the magnet and the wall of the tubing was not possible, so I settled for putting wedges down the two remaining sides. See the photo. This magnet will serve my classroom demonstrations very nicely. The price is reasonable, shipping was free with Prime, and the two-day shipping time was fantastic. I urge you to pursue reading on magnet safety. Have fun, enjoy these, and be safe! +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++.......................................................................................................................................................................... +.3

I purchased a pair of these 40 x 40 x 20 mm neodymium magnets and they are worth every penny. They are strong! I wd recommend these to anyone.

This magnet is extremely magnetic, nearly got my fingers pinched through the gloves when I was testing putting some tools on the magnet! Thankfully, I was wearing some thick gloves and prevented any bruising from happening from the pinch! I compared this to some fish magnets claiming to be "300 lbs" pull force and holy gawd this thing is even way stronger than that magnet! I suspect this might be because those fish magnets have a magnetic shield from their outer shell and the actual magnet is smaller than the shell itself. Anyway, this magnet is really thick even though it is small in your hands, this will literally crush fingers if not properly handled. A reminder when removing these 2 magnets apart though, do not let yourself be distracted after separating these 2 magnets apart. Once apart from each other put the one on the table far away from the one in your hand. If you do not do this it will fling itself to the other magnet and cause a powerful impact potentially breaking 1 or even both magnets, it may even pinch a finger! These types of magnets that are this powerful are known to be brittle and break easily if impacted by another magnet, so be in your best mind to follow precautions. Overall, this is a great magnet, helps me find screws, nails, and old tools that may be sticking out on the ground. Very useful and strong! Maybe sometimes too STRONG!

Theses are WAY too powerful ! I kinda blew it off as if all the reviews were overplaying it but they were correct. It takes of force and prying to separate the 2. Im worried they will come apart and then slam into each there and break. These are not a toy ! They're so strong that i sont know what you can even use these for but if you're wanting some really really strong magnets then these are it ! Im not lying at all these are POWERFUL ! I honestly cant even think of what you could use them for. I wish i could put these into something to use as a fishing magnet cuz they're perfect for that but theres no screws or any way to hook anything to them.

These magnets are every bit as strong as they are advertised, almost too strong for any practical application. The vendor mentions that they can be separated by sliding them. This is true, but they have to be separated by mechanical process. They had a plastic separator between them when they were shipped, and I could not get them separated without using an old breadboard which is the same width as one magnet and sliding them apart. Be VERY careful when separating, because the risk of them joining again and pinching you is high. I've worked with Neodymium magnets making brushless motors, speaker drivers, etc., so I have a lot of experience handling them. I ended up carefully combining the four magnets I had using a wedge, because separately, they were too much of a menace if they got anywhere near each other. I also wrapped them in vinyl tape so they wouldn't chip or break, plus that was the safest way to experiment with them. The four magnet set is stored in a PVC pipe with end caps since PVC is can't be crushed easily.