An absolute must have tool for Shimano (DA, Ultegra, etc.) crank users. If you have ever had an extremely difficult time trying to remove the crank bolt on the non-drive side crank arm, then look no further. This tool allows for easy installation and removal of the crank bolt. This can also be used with an Allen key (for extra leverage) for those times when the bolt feels like it has seized. Quality tool made of metal, so it won't strip like some of the existing plastic tools out there. Simple, effective and inexpensive.