i was referring to glow plugs but yes quality test gear is more accurate and durable. yet my auto ranging test meter cost me under a 100 bucks and does temp aswell and is true RMS. in my opinion unless its true RMS capable its not worth buying. and its the initial reading that you want. i happened to watch a vid from the states and the diesel mechanic was doing glow plugs on a 7lt ford v8 diesel and his point was change one change em all as its not much more work. and also that the initial reading was the important bit.

for glow-plugs i like NTK brand units part of the same company as NGK spark plugs.

You do realize that the RMS function (Root Mean Square) only applies to AC measurements right?

I hope NTK glow plugs are better than the NGK spark plugs because they are rubbish.

thanks for the feedback gents, some really good info there!
-didn't know about the RMS factor, but good to know there is a recommended range/ tolerance for resistance etc..think i will leave them alone as long as they meet spec.

-i prefer Autolite spark plugs but NGKs always had a good following and reputation in my circles

yes rms is only a thing for alternating currents. but with the little bit extra to have that function it makes sense to spend it. and have a better quality meter and often more features too.