Removing a cassette is near impossible without a proper lockring tool, which is why Park Tool hooks it up with the FR-5. 2 Cassette Lock Ring Tool. Designed to make your life a little easier, this lockring tool uses a one-inch base perfect for fitting on wrenches or bench vices, and makes it easy to remove cassettes without the removal of cones and locknuts. It has a 12-spline design, and works on Shimano, SRAM, SunRace, Chris King, and other cassette lockrings, along with some Shimano disc brake lockrings.