What is the name of the tool?

I have had amps with and without power meters and to tell you the truth, you don't need them.

Blasphemy!!

Thank you guys very much for you answers while not being arrogant. This is why a newbee like me wants to stick around.

I love meters. Mcintosh makes their own meters and takes pride in their accuracy. I’ve learned a lot from them, especially how little power is needed to make a decent amount of noise. Save up for them,their worth the extra money.

"...Mcintosh makes their own meters and takes pride in their accuracy..."
I just sold my Big Mac amp with those gorgeous power meters. But my Parasound A21 (or the JC1s for that matter) don't have any meters and they sound better to me. 
 

"... especially how little power is needed to make a decent amount of noise..."
So you are using the power meters to see how little power you are using? 1 watt goes a long way.....

Meters are too slow unless they are instantaneous peak reading with decay, read voltage, not power, and only if you know the amp voltage capability at all frequencies.

Most meters come under the classification of jewelry and are installed for appearance ONLY.

In the studio, we had a wall of amps, all without meters. Many studios have amps in separate rooms due to fan noise and the ability to duct in copious cold air to keep them happy. In million dollar+ studios, if power amp meters were of any use we'd have purchased them.

If you want to really know, use an oscilloscope. You can purchase an Android phone/PC based unit for under $100 Loto USB Oscilloscope OSC482M for Both Android Phone/Tablet & Windows PC, 2 Channels, 50M S/s, 20MHz (Bandwidth), 8~13 bit Vertical Resolution: Amazon.com: Industrial & Scientific

You won't know what the power is as you don't know the speaker impedance at the frequency in question, but by using Peak Hold function you will know how close you are to clipping. If you see an flat top peaks, you are clipping and your tweeters are probably not long for this world.

One caveat of using a scope on both channels at the same time is they must have a common GND terminal. Most amps do, but some use bridged outputs and may be destroyed by commoning GND.