Was looking to buy a Blackstone and saw this during my web searches.  I thought it would be nice to not have to store another piece of equipment in my garage, so even though it’s a bit costly, I took the plunge and ordered it for my 435 Weber.  It fits perfectly in the grill and must say it works perfectly.  I’ve cooked everything from bacon and eggs to smash burgers and the griddle works flawlessly.  I was concerned it may be cheaply made and might warp from the heat, but not the case, this is a heavy solid griddle and I’m happy with my purchase.