What is the name of the tool?


Forgive my absence of knowledge, but what is the name of the tool that one uses to measure the wattage coming out of ones speakers. I called it a watt meter to my family and got something that measures the watts and current coming from the outlet to the powered device I was using instead, for Christmas.  
rickytickytwo
Sansui made a light display "watt" meter. I had one in the 70s hooked to my AU 717.
Meters on amps aren’t necessary or really useful but they can be pretty 
Ampzilla with decade meters-4 orders of magnitude. VERY useful for training oneself, lower decade readings quite sensitive. I am a scientist, these things fascinate me.
Here is what it says in the McIntosh 501 owners manual.

• Illuminated Power Meter
The Illuminated Power Output Watt Meter on the MC501 is peak responding, and indicates the true power output of the amplifier. The Peak Watt Hold Mode allows the meter to temporarily stay at the highest power output and then slowly decay. The Front Panel Meter Illumination may be switched Off at any time.

I believe the meters are accurate. What I’ve learned from having them is I was amazed at how little power is used for normal easy listening. 1-2 watts does go a long way. Also when you crank it up I was amazed at how fast it can jump up and use several hundred watts.

I looked at the Parasound amps. Looks like nice stuff, I’m sure they sound nice. To me, they look a little plain.