Add two PCIe 4.0 x16 slots to a Mac that has run out of expansion room: the Echo II DV Desktop is a Thunderbolt 5 PCIe chassis built for the Apple MacBook Pro and Mac mini (with M4 Pro or M4 Max) and Mac Studio (with M4 Max or M3 Ultra). Its two PCIe 4.0 x16 slots take full-height, full-length cards, and each slot runs its own Thunderbolt 5 controller -- connected over two Thunderbolt 5 ports with two included Thunderbolt 5 cables, every installed card gets its own dedicated 6000 MB/s of bandwidth rather than sharing it with the other slot. That headroom suits bandwidth-hungry non-GPU I/O cards such as DV I/O capture cards, NVMe SSD storage cards and multiport 25Gb Ethernet adapters. An integrated 400W power supply with dual 75W auxiliary connectors and dual cooling fans keeps demanding cards powered and cool on the desktop.