I found what I was looking for Duntov!
It's on page 34 of the Coquard Cheese making supply catalogue out of France. http://www.coquard.fr/uk/cat.htm?34
They have two types, one coated with PTFE one not. The descriptions are:
ALUMINIUM ECLECTRIC HEATER
2000 W under 220 Volts. Thermostat : 20 to 100°C. Maxi temperature 70°C/80°C.
Bottom diameter 150 mm
Minimum height of immersion : 25 cm ; maximum: 65 cm. Total height : 90 cm.
Permits to heat 20 to 100 litres of milk. Doesn't burn milk. Accuracy : +/– 5°C on 100 L.
On 30 litres, temperature raises of 1°C in 1 min.
Ref : 037HCA
ALUMINIUM ELECTRIC HEATER WITH PTFE COVERING
PTFE covering (teflon) of the heating base
Power : 1700 W single phase 220 Volts. Electronic thermostat : 10 to 90°C.
Maximal temperature 70°C/80°C.
Bottom diameter 165 mm.
Minimum height of immersion : 10 cm ; maximum: 69 cm. Total height : 79 cm.
Permits to heat from 20 to 100 litres of milk. Accuracy : +/– 5°C on 100 L
On 50 litres, temperature raises of 5°C in 10 min.
I saw these used on some pretty beautiful raw milk cheeses. I'm going to check out pricing.