Patented Planetary Coaster Technology with Endless Coast 20% lighter than Rush V3 freecoaster hub6061-T6 shell & NDS jam nutNo gap when pedaling forwardMimics a cassette hub with an added dimension Pop & Go nylon hub guard included14mm hollow male cr-mo axleRR1s w9t Driver36HB/O 14mmAlloySilverRIM110455827272828UPC/EAN/GTIN: 888571092149