This case holds a Raspberry Pi and a 3.5" HDD. There are versions for the 3B and 4B. It can be fitted with a number of lids, including a TV tuner or a DVD drive, or a stack with both. The case is sized to match a standard DVD drive. The Pi and drive may be powered via a PiDrive cable as shown (which is becoming hard to find these days) or a powered USB hub. A small one can fit in the space above the HDD.
There are 5 lids: a thin lid (not shown in pictures), a plain 4mm thick lid, 2 DVD lids, and a lid with standoffs to hold the PCB from a Sony PlayTV dual tuner. The picture shows the case with the tuner lid upside down, so you can see the entry for the antenna coax. There is a DVD base and lids for the two main drive sizes (9.5mm ultra-slim and half-inch slim) along with a combo base that holds both DVD above and tuner below.
The V3 versions have provision for a 30mm fan above the pi. The photos don't show this version.
It can be used for a TV server (with HDD and dual tuner) or a TV client (with DVD drive). Or both in an all-in-one HTPC. The Pi may struggle; YMMV. You may also need a powered USB hub as the Pi supply may not be up to powering both drives.