Use a tool made by machining for machined bolts. The NC-machined protrusions perfectly mesh with the narrow grooves engraved on bolts.
KUROKO is a specialized tool for bolts and nuts that hold chainrings and cranks. Lock the two prongs onto a bolt at the back side of a chainring, and tighten it from the opposite side with an allen key.
This tool is used with a 6mm L-shaped hex wrench combined with its hole. Our STEX is recommended to use with since its short hex bit allows easy control. The pin in the middle stabilizes the work, but can be removed by screwing it.
Based on feedback from a typical press-made tool, we improved the mesh between the tool and bolts. You can also set the tool on a bolt and then combine the hexagonal wrench, which means you can start applying force at any angle you like, regardless of the direction of grooves.
The name comes from the people called KUROKO, who support behind the classic Japanese theatre, Kabuki. This tool may be inconspicuous and not often used, but it will definitely help you when in need.