Recently won the bid on Ebay for a pair of speaker wall mount brackets #290027827254. I checked JBL Pro and the mounts resemble the JBL-MTC-51 (black). Wondering what weight they are rated for? Some months ago I also won a pair of super heavy wall mount brackets that resemble another JBL wall mount. The JBL Pro site didn't seem to have much info on wall/ceiling mounts unless I missed something. I need 5 heavy duty wall or ceiling mounts for my 4301B and prefer to stick with JBL if possible. Peavey and Omnimount make comparable heavy duty wall/ceiling mounts and like JBL can be a bit pricey new $100++ each.