The new product is built around BCM2837B0, an updated version of the 64-bit Broadcom application processor used in Raspberry Pi 3B, which incorporates power integrity optimisations and a heat spreader (that's the shiny metal bit you can see in the photos). Together these allow us to reach higher clock frequencies (or to run at lower voltages to reduce power consumption) and to more accurately monitor and control the temperature of the chip. Dual-band wireless LAN and Bluetooth are provided by the Cypress CYW43455 "combo" chip, connected to a Proant PCB antenna similar to the one used on Raspberry Pi Zero W.