48mmスチール製メカナムホイールセット（左側2×右側2）

The overall design is fine (wish the inside spacers were hex shaped to allow for easier disassembly of the wheel), but a good 30% of the pins are way too loose. Several fell out just handling the wheel, not even while in use. Thankfully, the original manufacturer has CAD models, so I 3D printed hubs with built in pins which are working much better so far. The rollers work fine for this purpose.

I haven't had a chance to try them out in operation but they seem very well made. They're quite heavy: with the brass hubs each wheel weighs 73g, so four wheels together with hubs will be 293g. On a small robot that's a considerable amount of weight. There are lighter weight mecanum plastic wheels available, but these are very strong and have a load capacity of 3kg. If your robot doesn't need to carry 3kg and 293g ends up being more than the weight of your robot (mine without wheels and battery is about 120g), then perhaps the plastic Mecanums suit better. But if you want nice-looking, well-made stainless Mecanum wheels and have no issue with the weight, these are a very good choice.

I put these on a 3lbs combat robot just drive around with a powerful drive was enough to start breaking the pins that hold the rollers in place. I have been replacing the pins with m3 screws.