Air Purifier
Eschewing the boxy bodies of most purifiers, this one blends in with other wall art, inhaling particle-filled air through the small holes and expelling it through the "mouth" at the bottom.
Plain Air by Patrick Norguet for TLV, $1,800; tlv-belgium.be

Smoke Detector
Fire safety isn't known for its good looks, but with this sculptural smoke detector inserted into your wall or ceiling, it can be. The device runs on a 9-volt battery and can be linked to up to 12 other detectors.
Modern smoke detector by Architectural Devices, $33; architecturaldevices.com

Outlets and Jacks
Those generic rectangular covers are unsightly, but these electrical outlets (plus jacks for phone, cable, and data)are designed to be plastered over, leaving the plug flush with your wall.
Sets of 22 series outlets, jacks, and mounting plates by Bocci, from $250; bocci.ca

Sound System
Amina's in-wall speakers can be set into plaster or drywall to hide them entirely and to protect them from moisture, making them ideal for kitchens, pools, and bathrooms.
AIWX series speaker by Amina, from $1,000 a pair; animatechnologies.com

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