Base Slice
The Slice system has a footprint of 6.5-by-6.5-inch (17 by 17 cm), much smaller than a typical conference phone and smaller than a Mac Mini. Without any modules it's about 1.4 inches/4 cm high and weighs around 2.3 pounds/1.1 kg.
Collaboration Cover
The Collaboration Cover isn't a module, it's a $33 configuration option that adds touch phone controls for connecting and disconnecting calls, adjusting volume and muting. It also adds improved noise cancellation for the microphone. The controls only appear when the system's on, and they glow, which you can't tell here.
Audio Module
To turn the Slice into a high-quality conference phone, you snap on the $109 Audio Cover which adds a a set of Bang & Olufsen speakers. Without it, everything sounds kind of tinny, but if you use a headset that shouldn't be an issue.
Interface
The modules plug together via a USB-C interface.
Back
From left to right, that's a power button; charging connector; Ethernet connector; USB-C 3.1 connection; two USB-A ports (with a wireless dongle in one); DisplayPort and HDMI connectors; and Kensington lock slot. The Audio Cover (bottom) also has a separate Kensington slot.
Label sadness
The Elite Slice is a beautiful system -- until all those nonremovable labels get slapped on the front of it.
Ventilation
The copper accents are actually a 360-degree venting system.
Sans Audio Cover
Module connector
HP says the module connector is rated for at least 1,000 insertions.
Other end of the connector
Side
On the side of the system are a Thunderbolt-capable USB-C port and headphone jack. With a compatible monitor, you can power the system by connecting it through that USB-C port.