Product review (3 stars): 2 screws and 2 push-on terminals later I have a fully functioning compressor unit.  Thanks Amazon.
I did not purchase this relay/start capacitor from Amazon.com, but did have one of these in my A/C compressor unit which had been installed previously by my local HVAC company during an expensive compressor replacement.  The Supco unit lasted about 3 years.  The Supco SPP8E eventually exploded inside the compressor/evaporator housing leaving quite an impressive mess inside.  Lots of plastic film and back as soot paper everywhere.  Not hard to clean up, but the plastic housing of the capacitor was cracked and had blown completely off of the mount.  The start relay was dangling from it's connection wires.  I've had capacitors drop in value before and need to be replaced, but never one that exploded this severely.  Actually the A/C worked fine, but I started to notice that whenever the compressor came on in the evening, all the lights in my house would dim briefly.  I figured I'd better check the start capacitor in the compressor housing, but procrastinated several weeks. Boy, did I get a surprise when I finally opened the housing.  Fortunately, Amazon had this SPP8E replacement part in stock and available as 'Prime'.  Back up and running in short order.  Calling a service technician out on a weekend would have cost me hundreds and in my past experience this part alone would have been marked up 400-500 percent.  Two screws and two push on terminals later, I have a fully functioning compressor unit for just the cost of this part on Amazon.