Shucks, with 87 percent of the 4,400 reviews being 5 star, how could I go wrong. Unfortunately, with my new Yamaha RX-V481 receiver initially I could not make these banana plugs insert into the receiver/amplifier. It turns out the four metal "springs" on the side of the plug protruded way too much to fit in the jacks. I was prepared to rate them as 1 star but figured there must be another way. Sure enough, when I manually squeezed the four springs on each plug, they shifted inward enough that the plugs would then comfortably fit. Actually the plug is well built if it fits, so I'll give it four stars subtracting one star for no help addressing issues I've found after 30 minutes of research.
But what about all those 1 star reviewers that say the plug then forever slips out after the first insertion? Nope, not here - I could then remove and reinsert the plug numerous times with the banana plug staying firmly in place.
Then again, you may find your gear has a removable plastic plug inside the banana plug! If so, here's how to remove it: [...]
So bottom line, if you are plugging into a device with jacks that are a bit wide, then these are not the banana plugs for you! As it turns out the various sizes for banana plugs are: 0.8" (2mm aka "European") 0.125" (1/8 inch or 3mm is called a "miniature" or mini-banana)
Happy trails, Michael 0.16" (or 4mm is considered "regular" and is most common standard in the United States)