Thank to this bracket, you can install PC Engines APU2 board into cheap (approx. 20 €) mini-ITX case. The bracket is in two versions, one with Raspberry Pi and second without.

Something about my installation:

• Chieftec IX-03B-OP mini-ITX case
• APU2D4 is running pfSense

• Raspberry Pi 3 is running Pi-hole and UniFi Controller
  This can help: Step-By-Step guide how to install Raspberry Pi with UniFi Controller and Pi-hole from scratch (headless)

  APU2 COM2 (J3) connector is connected to Raspberry Pi GPIO header:

  APU2 COM2 RPi GPIO
  2 (TXD) o--------------------o 10 (RXD)
  3 (RXD) o--------------------o 8 (TXD)
  4 (GND) o--------------------o 6 (GND)
  5 (5V) o--------------------o 2 (5V)

Print instructions

Rafts: No

Supports: No

Resolution: 0.3

Infill: 40%

Filament: PM ABS black