Medium price cheapish Italian units. i saw one with the most bizzare fan speed control system ever, a multi tapped transformer (HUGE 40kg+) stepped 415v down to 400v and 380v for slow and medium speeds on two banks of three zeihl ahbegg type motors. the transformer must have cost a fortune and all it wanted was 2 pressure switches. no suction isolation valves, built like meccano etc, etc..........
2 x Copeland 6 cylinders from memory.