Endless Bike Company is a North Carolina based company that has started making cogs for single speeders. Their cogs are called Kick-Ass-Cogs and are a bit wider many you’ll find. They are actually a quarter inch wide (6.33mm). The extra width doesn’t allow the cog to damage your freehub body as easily. They are built out of 7075-T6 alloy with an engineered tooth profile to improve drivetrain life. They are available in 14T-25T. You can get them in their standard raw color or now they are offering anodized finishes in Pink, Orange, Gold, Blue, Black, Red, Green, Purple.
Check out Endless Bike Company website for availability and pricing information.
If alloy cogs aren’t your thing or you’d like to check out some more single speed drivetrain options you should check out what Jenson USA has to offer.