Double Six 1-er Convertor Single Speed adaptor kit for 8/9 speed cassette hubs. Pair of CNC machined aluminium spacers that look much sweeter than a bunch of washers to space out a &8216; Deep-tooth&8217; single sprocket. CNC Cr-Mo cogs have wide 7mm base to avoid ripping into the cassette body. Built-in offset optimises chainline. Supplied with 12T 5/64” cog* & lockring.* Note: are suitable for narrow 5/64” (9 speed) chains.