... and motorcycle, etc. Brand name famous brandSeries6000 6200 6300 6400 61800 61900 R series,F seriesRings MaterialStainless steel-440C,304 316 ,Chrome ... diameter(mm) Variant structure61800 10-320 Z,ZZ,RS, 2RS 61900 10-280 Z, ZZ,RS, 2RS, N,NR,ZN,ZNR16000 ...