This is a great machine. We only have one cow, but it really made our lives easier because she was not easy to milk. Initially we had trouble keeping the pressure up and getting the nozzles To make it even easier, we bought 4 3/4" plugs (see image) from the plumbing store, inserting them in the milk claw, then turning the machine on. It was a lot easier to keep the pressure up rather than trying to bend the tubes over to eliminate the airflow. Put the plugs in the milk claw before turning the machine on, then take them out one at a time before attaching to each teat. An inexpensive way to make the job easier. Be sure to measure to make sure they are the right size, or buy a couple sizes so they are tight enough to block the airflow.