Don't know but I've used the 2' thick ChemDry bonnets for encapping with my 17" rotary before I got my Cimex and it absolutely kicked butt over the synthetic with green stripe Queen bonnets I had been using.
Don't ask, I just 'happened' to come by three mildly used bonnets
Hardly get used now and even less in a few months when I look at adding my 2nd mex.
Still good for work in the warehouse though (rotary handle ceised in operating position and so not easily lifted in and out of vehicles.)
John