‘Are you wearing the earplugs?’ he asked his employer.
Artemis sighed deeply. ‘Yes, Butler. Though I hardly think we are in danger here. It’s a perfectly legal business meeting in broad daylight, for heaven’s sake.’
The earplugs were actually sonic filter sponges, cannibalized from fairy Lower Elements Police helmets. Butler had obtained the helmets, along with a treasure trove of fairy technology, over a year previously when one of Artemis’s schemes pitted him against a fairy SWAT team. The sponges were grown in LEP labs, and had tiny porous membranes that sealed automatically when decibel levels surpassed safety standards.

The Eternity Code, Chapter 1