The Subaural Bomb, is a device created by the Styx that knocks everything in its blast radius unconcious. There's a variation of this technology called Subaural Field, which they put up around the entrances to the Colony to knock out anyone trying to escape.
This bomb was used during Freefall by Oscar Embers against Celia Burrows and Drake's team. It was conceled as a shopping trolley, but Celia noticed it was oversized, which make her suspiscious. It was rectangular, and instead of the usual bright tartan or florid flowery fabric, it was covered in a dun brown material. It also had sturdier wheels than normal trolleys.
When Oscar Embers pressed a button on the top of the 'trolley' a low tone cut through the air, quickly building in volume. It grew louder enough for the victims' teeth to chatter and then the tone dropped an octave, then another, then several more, until it couldn't even be heard as a rumble.
Celia felt as if a knife was being dragged down her spinal cord, making each of her limbs twitch uncontrollably. The sound was described as 'beyond the limits of human hearing' and 'unbearable'.
When Oscar Embers hit another button, the fabric panels on the sides of the trolley were blown off, revealing a chunk of machinery underneath. Its sides were gloss black, although inset with concave dish-like hollows of varying sizes that appeared silvery, like liquid mercury. Then, an explosion took place as a concussive wave was thrown out by the device in an 'invisible wall of sub-audible sound that only affected living things'.
Everything in its radius was knocked insensible, affecting people, dogs and even birds.
Both Oscar Embers and Mrs Tantrumi used ear plugs to avoid the effects of the bomb.