Hands down, the best fixed gear cog and lockring removal and installation tool ever made. The cogs or lockrings rest in the channel while the hook grabs one tooth or the lockring slot to tighten or loosen without any slippage. You heard it correctly - no slip installation or removal. It will not mar or damage the cogs or lockrings due to the tight tolerances.
The rear of the tool features a 15mm hex recession for wheel locknuts and a 5mm hex for use with an MKS chain tensioner. Both front and back of the tool are polished to a high luster. Expensive, yes. But this forged tool will last a lifetime, protect expensive cogs and is an absolute pleasure to use.