California Division of Measurement Standards has approved several EZ Meter models for revenue billing within the state. Before they can be installed, they must be tested by the local Weights and Measures inspector. See further details on the main web site about California meters.
The only meters approved by the state are:
Sequoia - 120 volts to neutral, usually used in marina or RV park for a single boat or vehicle plugged into a 30 amp receptacle.
Denali - like the Sequoia, but serves two separate boats or RVs.
Yosemite - your basic 120/240 volt service found everywhere.
Yellowstone - standard 120/208 volt three phase wye. Due to power company tariffs, rarely used in California for revenue submetering.