I bought these guards to block heat from getting to the side shelves, as I badly burned a finger on a hot plate.  They worked well for that, but I don’t like how they attach by booking over the edges of the griddle top - makes cleaning more difficult.   Not using the rear guard for this reason.  The Blackstone should come standard with metal skirts that block off the side openings, and should not hook over the top of the griddle.