Real time clock and mSATA interface for RPi

2. The second function of the extension card is that of a real time clock  (RTC) PCF8563. This allows the computer to set the correct time even if it’s not connected to a network. The way it does this is also described in the documentation (see below).
 
Convert your Raspberry Pi into a Desktop PC - board - battery holder
The female GPIO connector and the battery holder for the real time clock.
 
Convert your Raspberry Pi into a Desktop PC - mSATA connector
mSATA connector for SSD < 1 TB
3. The most spectacular for the three functions is the addition of an mSATA connector (the m is for mini) where a mass storage module can be connected, from which it is even possible to boot the RPi. This mSATA interface is intended for an SSD (Solid State Drive) mass storage module, not for a standard hard disk.
Even though this interface passes over the USB of the RPi (via the USB to SATA bridge controller GL830) – which considerably restricts its performance – the balance is still favourable, both in terms of capacity and in terms of the speed of access to the mass storage SSD. But one must take into account the question of the price of the SSD module.

The eye of the Pi Desktop

Convert your Raspberry Pi into a Desktop PC - camera
The camera module is not included.
So you’re getting a real desktop computer, with four USB ports, Wi-Fi, Bluetooth, Ethernet and HDMI. And on the case an indicator light which shows the status of the computer: on, off, booting, shutting down… But that’s not all.
In the Pi Desktop case, there is also a place for a RPi camera module . This is not included in the kit, but there is an opening in a good place in the side of the case.
In this case, the camera is connected directly to the RPi.

Heat dissipation and ventilation of the Raspberry Pi

In this case that is as full as an egg, there is a lot of heat dissipation. For this reason the kit contains a heatsink to stick onto the microcontroller of the RPi.
Convert your Raspberry Pi into a Desktop PC - bottom view
To hang the case. 

it’s noticeable that the case is well ventilated, with numerous vents. According to some users, this is insufficient to the point, they say, that a small fan is needed to keep the temperature of the Pi Desktop within reasonable limits. As the bottom of the case has slots suitable for wall mounting, it’s possible that vertical mounting may give better ventilation.