This model will need to be printed with supports on the build-plate only, everything else is an achievable overhang. Printed with PETG on my MK3S+. This also has a mount and duct for a 3010 fan of whatever voltage, i recommend a 3010 but you can use any 30mm fan. I have used some printed M3 drop in t-nuts and some M3x15mm socket-cap screws for mounting of the casing itself and i used 4 M3x12mm socket cap screws for the fan itself. 

You will have to drill out the fans mounting holes as well as im not that good at 3D modeling just yet. I used a 3mm drill (or a 7/64) and the screws will cut there own threads on the way in

INSIDE DIMENSIONS: L=45mm, W=15mm and D=23mm

T-NUTS: https://www.printables.com/model/116299-insert-tnut-for-3030-alu-profil/files