Park Tool FR-7C Falcon Freewheel Remover
This is a core tool for any home or professional mechanic. You cannot call yourself a bicycle mechanic and not own this tool. Fits Shimano, SRAM, Chris King, DT and other Shimano-type cassette lockrings. The FR-5 also fits Shimano disc brake lockrings. Does not fit Campagnolo lockrings.