Fuel flow meter?

[79jasper]

Does anybody know what these are used for? And what "useful" information would they give?
http://www.dan-marcrvparts.com/rv-and-marine-parts-fuel-flow-meters.html

Definitely not looking to buy/use one. Just saw them and wandered what exactly they're used for.

 

[Maverick1701]

I have only seen them on boats...never on an RV.

On boats they are used to find the best rpm for optimal fuel efficiency.

 

[79jasper]

Ah I see. Makes sense too.