Summary Hello my friends! (= After a few months, I understood need to try another fans, instead 4010 model. So I bought radial fans, and I designed the new fan holder. What can I say... It's AWESOME! Super flow and without cooling of hotend. If you using x carriage for Re-D-Bot, and you want use new fan holder with volcano, I recommend increase holes (bellow you can find image) or use updated version (Carriage_base_back.STL you can find there). This fans is pretty powerful, and main printing going on 40-50% of fan power. If you want reduce noise of fans, in Marlin you can turn on sofware PWM for fans. You need uncomment this in Configuration.h #define FAN_SOFT_PWM Video of print test: https://youtu.be/MXtuoXqMKMM P'S: In files I published "Fan_duct_filament_V2_nozzle_x2.STL" sources, so you can design your nozzles, with your own forms and sizes. I used this fans.They are pretty good, I recommend (; http://ali.pub/stfgx Print Settings Printer: Re-D-Bot Rafts: No Supports: Yes Resolution: 0.2 Infill: 30% Notes: Supports is not required, but can help get better quality (; About Assembly For assembly you will need to print main fan holder (Fan_duct_filament_V2.STL) and two nozzles (Fan_duct_filament_V2_nozzle_x2.STL). All screws (4), nuts (4) and washers(6) has M3 size. Two fans like this. Sorry, forgot put nozzles in photo >_ How I printed. Supports are not necessary, but helped get better quality. I like quality :P Preparing screws with nuts Mount the fans Well done! (= Now, connect nozzles and done. In Finally, just unscrew old fan and replace by this. Update Carriage_base_back.STL of Re-D-Bot x-carriage for Volcano (just recommended, not required). You can increase holes of your current printed element, but will be careful.