The “Original” Dual Baffle

I was setting up my drums at a live gig, and I saw the sound engineer slip a thin baffle in front of the guitar amp to reduce the volume out front. I was checking it out, and he offered to place one on the backside of this open-back amp too, which was still kind of blasting me on the drums. Whoa! Big difference! I was intrigued. Not only is this baffle “amp-sized,” but it is also covered with Tolex and grill cloth (like amps and speaker cabinets), so it looks like an amp on stage. What is this magical device? I had to find out and try one in my studio.