I regularly go through PLUG headphones, using them everyday at work, they are amazing at blocking sound(I install interior trim), and the cord normally takes about 6 months to wear out and crack somewhere, so I just buy another pair. This time around I saw this pack and was exited because I could see there were some different sizes(in the past, PLUG headphones shipped with one size plug), so I ordered it along with 2 new pairs of PLUG headphones. Upon receiving items, I found that KOSS had decided to include two sizes of plugs with the headphones themselves, the normal size, and ones a bit larger. The pack of replacement plugs had three different kinds, 2 normal size cushions, 2 large cushions, and two rubber based plugs similar to reusable earplugs. This was a bit disappointing as all I wanted was slightly bigger than normal cushion style plugs, the rubber ones don't block as much sound. And since the large cushions were already included with the headphones themselves now, my purchase was somewhat useless to me. FYI, the larger cushion plugs(albeit included with the headphones) do block out a bit more sound than the smaller ones, but are just a hair uncomfortable for me, even though I still wear them.
The Bottom Line: Unless you want the rubber based plugs or really need a replacement pair, you will get no new sizes with this pack, the small and large are already bundled with the new headphones themselves(this is new, used to be just one size included). I hope this helps some people not spend $10 if they don't need to.