Quality of product is very good, sturdy materials. Sadly, on an Engl 212 cab which meets all the requirements for the use of the Gravity CL01, it doesn't stand out where it should: stability.
The rubber foot on the holder is, after installation, located exactly where the cavity of the cab handle is. Because of that even a single sm57 mic is too heavy and the clamp shifts down.
I'd imagine more 2x12 cabs have handles on the side? So, unless you have no side handles, this is prolly more for 4x12 cabs I'd say.