Sum is a portable speaker concept for Sonos, designed to be paired on-the-go with nearby Sums. At a picnic, in a car or at a party you can create a symphony with friends with individual Sums linked up. The form language of Sum is in respect to pure geometries found commonly in other models of Sonos, especially Sonos Beam and One. The design details have strong references to Sonos One as Sum is slightly smaller yet in a similar scale. The lock button and strap are key elements of Sum that add to its portability. This concept predates Move, a portable speaker by Sonos.