. This is very good for printing small objects faster. Also I experienced that it's possible to print about 30mm in horizontal direction. So you can setup the bridge distance in slic3r to a bigger distance and it's easier to remove these after printing :-) The electric controll is based on the Gcode conrolled Fan Mod of Ian Johnson (http://solidoodletips.wordpress.com/2012/10/26/gcode-controlled-extruder-fan/) but instead of a Fan i used a relais that switches an air pump for aquaria. there are really cheap ones for only 10Euro ( about 13$). I designed the Tubes (i wasnt supposed to look like .... ! :D ) and they really fit very well with a glue simply made of Aceton and ABS plastic. Also it looks good when you paint them in copper or iron colours. ;-)You need : -Air pump ( i used a 66 Gallons/hour, 5Watt, Membranepump, bought at Amazon for 10Euro) ( http://www.amazon.com/s/ref=nb_sb_noss?url=search-alias%3Daps&field-keywords=air+pump+aquarium&rh=i%3Aaps%2Ck%3Aair+pump+aquarium ) -All the parts for Ians Guide ( but not the fan) ( http://solidoodletips.wordpress.com/2012/10/26/gcode-controlled-extruder-fan/ ) -12V DC relais (you have to take a look how much power your pump has to buy a relais that can switch that power. -A flexible tube (inner diameter 4mm, outer 6mm) -A glue that dry´s very quick. I used a acetone and ABS mixture. For the electric part you just have to follow Ian Johnsons guide but instead of connecting the Fan you connect the 12V relais ( you can also use a transistor or something like that ;-) ) . Take a look at the scam for detailed informations. After the hardware is connected, its very important to set up the controll of your "fan" (in our case the air pump). I can only say how to adjust it in the Slic3r Menu (which Repetier-Host uses for example) : Go in your Slic3r Settings->Filament Settings->Cooling Then you do the following adjustments: -Fanspeed minimum to 100 -Fanspeed maximum to 100 -Bridges fan speed to 100% -Disable fan for the first 1 layers ( maybe adjust to 2, you have to see how the layer behave) I exchanged my Hot Head against this one http://www.thingiverse.com/thing:33152 from tek so if you have another hot head you may have to customize this cooler tube system. If you have any questions, just ask me per pm or in the Comments. P.S. : Sorry for my bad english, but i learned it in school 10 years ago :)