This switch from Qnap provides high-speed connectivity throughout. There are four fixed SFP+ ports and eight SFP+ or RJ45 ports that can be freely combined. So one port is either RJ45 or SFP+, as desired. Therefore there are 16 slots for eight ports.
For us Mac users, this has the advantage of being able to connect up to eight Macs with RJ45 10 Gbit ports, but with the rest of them being able to use the more modern and economical fiber optic cable.