The specialty tools needed to remove and install a Shimano, SRAM, Chris King, American Classic and Sun Race freehub cassette is a Park Tool FR-5, FR-5.2 or FR-5G lock-ring tool and a Park Tool chain whip or pliers. The Park Tool FR-5G comes with a guide pin that fits into the hollow axle where the quick release goes, and is used to keep the tool perpendicular to the lock-ring while the lock-ring is installed or removed. The Park Tool FR-5 is an older part number and has been replaced with the Park Tool FR-5.2. To remove a cassette you must keep the cassette from turning while removing the lock-ring, and a Park Tool SR-1 chain whip or Park Tool CP-1 chain whip pliers can hold the cassette from turning. The chain whip and pliers tools can be used on 7, 8, 9 and 10 speed cassettes; maybe others so read the product description. Park Tools makes quality tools and are considered higher priced bicycle tools. You can find cheaper alternatives, but you will sacrifice quality.
You will also need either a wrench, adjustable wrench or a ratchet and socket to turn your FR tool, as well as a torque wrench if you know the torque spec for your cassette lock-ring.
Here is a list of the Park Tools mentioned above on Amazon for purchase or to read the reviews:
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