Surly Single Speed Cog

They Say:

Shimano compatible Spline fitting.

9 Speed spaced, these cogs can be run 9 speed or less, together with Shimano 9 Speed gear shifter systems.

The large foot print caused by built-in spacing at the base of these machined sprockets gives a larger foothold on the cassette body,
making these a premium selection for Single Speed or multi-speed use with reduced risk of torque transfer damage to the cassette hub body. (Note: This point is especially important with Alloy or Ti Cassette bodies)

• CNC machined hardened SCM 415 Cr-Mo Steel.
• Shimano HG Spline, 9 Speed spaced.
• Ideal for Single Speed use.
• Large Anti-Dig footprint on cassette body.
• Chrome Plated.