Models HP932A, HP932B are rated for long life at elevated temperatures. The heated plate is made of cast iron, and the housing of stainless steel.
  Temperature is regulated with an infinite power control set on a numbered dial. 
  Other features include an on-off switch, and a 5-foot cord with plug. Overall size: 10-in diameter x 9-in high.

Compare to Chromalox ROPH

Model HP18S16 Hot Plate shown with a 5-gallon. stock pot.  Note thatthe thermocouple from the remote thermostat is immersed in the pot so that the hot plate is controlled using the temperature of the fluid rather than the plate surface
Model HP22S36 is a 22-inch diameter hot plate shown on optional casters, with extra power for warming a full 55-gallon drum. Temperature is controlled with AN OPTIONAL REMOTE DIGITAL thermostat
All models include a steel heated plate except Models HP932A and HP932B, which are cast iron. Housings are made from stainless steel. Thermostats can be mounted or remote. Digital thermostats are optional at extra cost. Higher load ratings are available
Model Size/ inches Power/Watts Voltage Max temp/F Temperature  Control Maximum load/lbs
HP932A 10 dia x 9 high 2050 120 1000 Variable power 120
HP932B 10 dia x 9 high 2050 240 1 ph 1000 Variable power 120
HP12S13 12 dia x 5 high 1500 120 700 Variable thermostat 250
HP12S34 12 dia x 5 high 5300 240 1ph 800 Variable thermostat 250
HP18S16 18 dia x 5 high 6300 240 1ph or 3ph    750 Variable thermostat 550
HP22S23 22 dia x 5 high 9000 240 1ph or 3ph    700 Variable thermostat 825
HP22S36 22 dia x 5 high 13500 240 1ph or 3ph    750 Variable thermostat 825
HP22S42 22 dia x 5 high 15900 240,480,1ph
or 3 ph
800 Variable thermostat 825
bullet Model HP18S16 will heat 20 gallons of water in a covered stock pot from 70F to 210F in 2 hours
bullet Model HP22S42 will heat 20 gallons from 70F to 210F in 55 minutes.
bullet Due to lower specific heat values, most liquids and blends will heat faster than water