I bought one of the cheap ones at pep boys and it worked fine until it got stuck on the cap. It was size "B" I believe.
Last time I had the car in the shop, my mech took it off and I never got it back.
Bought a replacement, same exact one I had before, and this one was a fraction too small. figured if I could get it on I would leave it there. it was so cheap the square hole for the ratchet broke off of it. LOL
I used a pair of huge vise grips and a towel on it to stop it from damaging the top in order to knock it loose then untwisted it by hand. Worked for me in a pinch.
I'd rather get the mb factory tool, or the one gilly mentioned.
'92 300CE - Sold
2004 C240 - C7 Wheels
2015 ML350 - P1, Pano, Ash poplar wood, Sport Dinamica interior, Running Boards Keyless go.