I had a very tight spot to remove a ABS fitting from my sewer line 3 inch pipe. This Flange-Off requires a 1/2 drill or adapting a 3/8 inch drill chuck to fit the approximately 7/16 hex drive. This narrow space required me using a right 1/2 inch angle air ratchet (Ingersoll-Rand 1077XPA Heavy Duty 1/2-Inch Pnuematic Ratchet Wrench) using a 1/2 square drive quick change impact adapter to a 7/16 hex drive by Milwaukee 48-66-0061.Be warned that the Flange-Off hex drive end is not really 7/16 but rather 11 mm or so. My quick change impact adapter damaged the hex on the Flange off enough to become permanently attached to the device. The Mandrill on the Flange-Off cannot be changed as it is one with theI did not use a 1/2 inch drill because I had limited space to work in and no right angle 1/2 drill was small enough to fit into the space. The Ingersoll-Rand 1077XPA Heavy Duty 1/2-Inch Pnuematic Ratchet Wrench has a very small head for confined spaces. Be warned that the Ingersoll-Rand 1077XPA Heavy Duty 1/2-Inch Pnuematic Ratchet Wrench is not designed for this work, and violates the warranty. But it worked perfectly without binding and at 90 PSI was slow enough to do the job without melting under light pressure. Even when it bound up exceeding the torque, it would just stall and not whip around or injure me. Practice on a piece of wood to get the feel if you try this wrench.I had to increase the workspace to 7 1/2 inches to get the tool in there so I cut the fitting back with a hacksaw blade on a reciprocating saber saw. This gave a smooth starting surface.The key to the the flange off is the center guid which keeps the teeth of the hole saw aligned. Take it slow and tap the center guide deeper as you go along. It was worth spending money on these tools as it saved me from having to redo all of my plumbing because I was able to glue a new fitting on to the existing ABS. I hope this is helpful.