This is a high quality, 32 hole, pre hyperglide 6 speed cassette road hub (model 6207) produced in the early 1980s as part of the popular 600EX component group. It requires the use of a Shimano UNIGLIDE 6 speed cassette (though NOT a Dura Ace uniglide cassette), where the smallest cog threads onto the hub and acts as the lockring. A Shimano uniglide (UG) 7 speed cassette can also be used but would require that a 1mm axle spacer be added to the drive side (right) of the axle, or use 8 speed spacers. This would be a good hub to consider if your frame is limited to 126mm rear dropout spacing. Polished aluminum shell. Quick release skewer sold separately. NEW old stock!