I would like to have a model #100398 modified as follows :

Voltage range of 0.0 to 30.0 vdc and current range of 0 to 300 amps.

This arrangement would be great for car audio, off-road vehicles, service utility vehicles…..etc. anywhere monitoring of voltage/ampere output of the ALTERNATOR is desired.  Shunt type meters are not useful in the vast majority of automotive applications as most vehicles are negative ground and starters would smoke the shunt plus people with high load accessories want to monitor their high output alternators performance.  If you were to produce this product in this configuration (and include a long harness)and market it for automotive purposes  I’ll bet that you will sell a lot of them !