I bought a white PBT spacebar from QTan's store, and a blank set for the KC84 from Taoabo. It is PBT also, and its spacebar fits the FC660M also. I got the black one, but there is also white. Most standard space bars does not fit the FC660M. Also, the right shift is not standard, because it is 2.25u, the same size the standard left shift. Finally the windows key is 1u, instead 1.25u. Those three caps are different than standard ANSI layout. PBT plastic is more resistance to wear, thus it does not get that ugly shine that ABS tends to get quite easy.