This is a cooling duct for the Makerfarm Prusa i# for a E3D v5 hotend. After installing the E3D I starting getting the same warping issues that I was getting with the magma hotend and ABS until in installed papergeek's duct. I found MikeP-NZ's duct and added the extra duct out the back. I printed in 2 halves then used this method to weld them together I used a half round file to adjust the opening for the E3D heatsink to slide into and ensured it was a snug fit. I ran some silicon around where the fan sits against the duct to seal it. The fan cover from papergeek's magma hotend duct needs to the printed at 75% scale to fit the 30mm fan.