As you can see from the photo, I have 4 x Raspberry Pi 4B's stcked up, and an RS485 HAT on top. I know the work area looks a bit untidy, but can you imagine how much of a "spread-out" mess, it would be without using the Cluster Case. I was worried about the Cluster Case, reducing air flow around the Raspberry Pi's and worried they might get hot. I then realised the fans had never switched on. So, I just ran the command vcgencmd measure_temp to check the Raspberry Pi's temperature, and it's only 33 degrees. So, to summarise; 1. Tidier desk, working area. 2. No over-heating very happy, Thanks Mike