The Primacoustic RX12-HF Recoil Stabilizer is an isolation platform for large studio monitors and subwoofers, measuring 20 x 13 inches (508 x 330 mm). It is used in recording studios, mixing and mastering rooms, broadcast suites and home studios to decouple a speaker from the desk, console bridge, shelf or stand it sits on, so that cabinet vibration does not excite the surface and smear the low end, and so that the woofer's recoil energy is resisted by mass rather than lost into soft foam. The construction is a three-layer sandwich: a high-density polyurethane foam base that isolates the speaker from the supporting surface, a heavy 1/4 inch laser-cut steel deck with black powder-coat finish that adds stabilising mass, and a thin 1/8 inch neoprene top pad that grips the speaker. This HF (horizontal-fire) version is flat, so the monitor fires straight ahead in the horizontal plane; down-fire and up-fire angled versions are sold separately. It is 67.5 mm high, supports speakers up to 40 kg (88 lb) and weighs about 10 kg.