Yes, this is the worst 28mm cube I have ever tried! It is also the best 28mm cube I have ever tried! Why? It is the only 28mm cube I have ever tried, no, it doesn’t perform well but if you want a 28mm cube then get this, if you can allow the extra 2mm then get the gan 330 or meilong 30mm cube. This cube is simply an individual one of the cubes used in the Gan Mosaic sets.
You can buy it here: https://speedcubing.org/products/gan-328-keychain
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I think the worst cubes I've ever seen are off-brand non magnetic non speed cubes on ebay, although some of them are probably better than the official rubiks brand 😂
eh
for me its whole purpose is just to be a key chain lol