Dual color printing - 1.75 mm filament

3 x pneumatic couplings 1/4 with a 4,1 mm hole going through..
You can find it here:

http://www.aliexpress.com/
Product ID: 32361630920

https://www.youtube.com/watch?v=6GYKkcXckPQ
You can download file car_plus.amf with Cura and print it like in video:
https://www.youtube.com/watch?v=KwA6fZ4u9Wo