It must be acrylic, since the option of a black platter was mentioned, and I'm not aware of Lexan (polycarbonate) being available in black. Also, as YNWaN says, polycarbonate does have different look to it. It's also (I'm reliably informed) very tricky to machine and expensive as a result. Whatever, the Timestep platter will result in a quite different sonic feel to that of the MN platter. Which is best can only be determined by listening.