O2 sensor tools that have a split down the side are good for installing the sensor. They may or may not be adequate for REMOVING the sensor.
I gave up. I bought a Wright deep-well, 6-point impact socket. Clip the wire, the Wright socket has broaching all the way down, so there's room in the socket for the sensor body (unlike most deep sockets that have shallow broaching, and no room for the sensor body.)
For the record, Wright is a family-owned, USA-manufacture tool company that doesn't get a lot of exposure because their primary market is industrial applications--mines, oil refinery, construction--not automotive. Their pricing is also much nicer than, for example, Snap-On.
www.amazon.com/dp/B002VKBRCC/?coliid=I3QM27R5Q6EZ28&colid=2VLYZKC3HBBDO&psc=1&ref_=list_c_wl_lv_ov_lig_dp_it