Worked a treat on my Zafira Tourer (2016) rear wiper arm, which was stuck on even when the nut had been removed. The arm wasn't budging at all, so I bought this. It was due to arrive the following day, so that night I liberally applied WD40 to the arm and the bolt it was stuck to, surrounding the lot with a cloth to catch the excess.
This arrived at 15:14 the following day. By 15:18, the arm was off. It is plenty big enough for the bolt on the rear wiper of my Zafira Tourer and absolutely simple to use. Loosened the nut, fed the teeth of this under the arem, lined up the screw with the bolt on the car and turned until tight. Then I just gently rocked the arm towards and away from me (like I'd seen on YouTube) and the arm just popped off with an anticlimactic "pop".
TLDR - this fits the rear wiper arm of a Zafira Tourer and works great.