It looks to me that the fans are 1.5" 12vdc fan. Check Amazon, similar to some computer fan found on some server boxes.
You probably don't want 1U server fans... they're probably pwm controlled and include a tach (4 wires), and they usually turn up to 15000 rpm and make quite a bit of noise, plus they're over an inch long. I'd suggest looking for a 4010 DC brushless. They're easy to be had in 12v, and pull little power (0.1 - 0.2A) and Digi and Mouser certainly would have them, but they can also be found on AllElectronics.com 12V@0.08A! And $3.75 ... And they have rubber mounts, and fan guards $1 for either https://www.allelect...ling-fan/1.html
Edited by TomTTuttle, 28 September 2019 - 11:09 AM.