Manually machined Copper Tungsten (70% Tungsten/30% Copper) rod with a 3/32"" ceramic ball tip.
Spin times average from 3-6 minutes. Micro's can be a challenge to spin but fun little tops to carry around.
If you aren't familiar with Tungsten the main thing you need to know is that it's incredibly dense and heavy. The extra weight with this micro means easier spinning and longer spin times then a standard micro top.